Tilapia In Recirculation Systems.

[Tilapia]

Dear all.

I would like to know if any in this forum, have knowledge about where to buy bio-media, for filtration in recirculation systems. The suppliers I have seen and contacted, must think that it is made of gold, because they charge just about the same. Or if someone know a plastic-factory, where it is possible to place a direct order, to avoid a middle-man.

Thanks.

Tilapia.

[chownah]

Will a slow sand filter work...it is bio-filtration...it only requires white sand as a filter medium.

Chownah

[Tilapia]

Will a slow sand filter work...it is bio-filtration...it only requires white sand as a filter medium.

Chownah

Hi Chownah.

With the water-flow I have, a sand-filter will be to slow (unless it is huge) I change 153m3 of water/hour, so I need a plastic material with a large surface area, for the moment I use water-bottle caps, where we punch a hole in them, for better water-flow, they are ok as long as we keep the stocking density around 50kg/m3 of water, but we want to increase the density to 75-90kg/m3 and then the caps just wont do the job. In the US the good farms operate with 120kg/m3

Tilapia.

[Somtham]

Dear all.

I would like to know if any in this forum, have knowledge about where to buy bio-media, for filtration in recirculation systems. The suppliers I have seen and contacted, must think that it is made of gold, because they charge just about the same. Or if someone know a plastic-factory, where it is possible to place a direct order, to avoid a middle-man.

Thanks.

Tilapia.

Last year I searched for them but was unable to find any. I did find some paper/cardboard ones that look just like the plastic biofilters. They have a huge surface area and are used for cooling pig pens. From what I've seen the farmers will make an entire wall of them and then pump water to the top where it trickles down the 'filter' with huge fans that blow the cool air across the pen. You can probably find them in most ag stores.

rgds

[Khonwan]

Biofiltration_System.xlsMy attachment shows a filtration system I've drawn up recently since I've been considering intensive fish rearing. I believe sand could be used as one of the terminal filter mediums. I believe the problem of water flow in connection with sand may be resolved by simply limiting the depth of sand used.

My example shows a 100-pipe system, but that is just for my own potential future large project. The system can easily be started with only a few pipes and then be extended as needs dictate.

All feedback welcome.

Tilapia, What FCR are you achieving with your Pla Taptim?

Rgds

Khonwan

[Tilapia]

Biofiltration_System.xlsMy attachment shows a filtration system I've drawn up recently since I've been considering intensive fish rearing. I believe sand could be used as one of the terminal filter mediums. I believe the problem of water flow in connection with sand may be resolved by simply limiting the depth of sand used.

My example shows a 100-pipe system, but that is just for my own potential future large project. The system can easily be started with only a few pipes and then be extended as needs dictate.

All feedback welcome.

Tilapia, What FCR are you achieving with your Pla Taptim?

Rgds

Khonwan

Hi Khonwan.

I wasent able to download the file, for some strange reason, I will see if I can find the problem. Our FCR with red Tilapia is between 1,4 to 1,6 and I exspect it to be better as we improve our system and the feed, we have the privilege to experiment with different nutrision and protein levels, but the main-key to succes is the water-quality, that is above all.

Best regards.

Tilapia

[chownah]

Tilapia,

You need not worry about getting a couple hundred cubic metres per hour from a slow sand filter....they are often used for municipal water supplies so just about any flow rate can be achieved.

Chownah

[Somtham]

Tilapia,

You need not worry about getting a couple hundred cubic metres per hour from a slow sand filter....they are often used for municipal water supplies so just about any flow rate can be achieved.

Chownah

I had built a sand filter last year for cleaning bore hole water for the ponds and used a rate of 0.5GPM/sq ft of filter and put in a 500 sq ft filter. I once tried to run the settling pond water through it and it plugged up in a day. Thank God the filter literally blew up, no rebar in the concrete, because it was a constant chore washing the top layer of sand. Even our new sand filter for house use and plant watering needs to be cleaned every 6 weeks. But the water coming from it is clear and tasty.

Municipal water supplies are not cleaning fish poop through their sand filters and I would approach that idea with extreme caution.

rgds

[Khonwan]

Hi Khonwan.

I wasent able to download the file, for some strange reason, I will see if I can find the problem. Our FCR with red Tilapia is between 1,4 to 1,6 and I exspect it to be better as we improve our system and the feed, we have the privilege to experiment with different nutrision and protein levels, but the main-key to succes is the water-quality, that is above all.

Best regards.

Tilapia

Hi Talapia

I've just emailed you (via ) with my email address. Should you wish, reply to my email address and I'll email the file in a format suitable for you.

Rgds

Khonwan

[chownah]

Tilapia,

You need not worry about getting a couple hundred cubic metres per hour from a slow sand filter....they are often used for municipal water supplies so just about any flow rate can be achieved.

Chownah

I had built a sand filter last year for cleaning bore hole water for the ponds and used a rate of 0.5GPM/sq ft of filter and put in a 500 sq ft filter. I once tried to run the settling pond water through it and it plugged up in a day. Thank God the filter literally blew up, no rebar in the concrete, because it was a constant chore washing the top layer of sand. Even our new sand filter for house use and plant watering needs to be cleaned every 6 weeks. But the water coming from it is clear and tasty.

Municipal water supplies are not cleaning fish poop through their sand filters and I would approach that idea with extreme caution.

rgds

Thanks for the reply. Indeed, suspended solids plug sand filters quickly and I agree that approaching the idea of using a slow sand filter should be approached with caution. A couple of questions. When you pumped your settling pond water into your 500 sq. ft. slow sand filter did it have suspended solids?....and was it these suspended solids that plugged the filter? Also, can you describe the construction of your 500 sq. ft. slow sand filter?

I guess that I'm asking about this because municipal water supply slow sand filters are considered to be a very cost effective way to clean water so long as sufficient land is available for constructing the facility. It might be that a fish pond is too small of a system to take advantage of the efficiencies available with a full on slow sand filtering system...I don't know...but would like to work on this. Your help by explaining your experiences is appreciated.

Chownah

[Somtham]

Tilapia,

You need not worry about getting a couple hundred cubic metres per hour from a slow sand filter....they are often used for municipal water supplies so just about any flow rate can be achieved.

Chownah

I had built a sand filter last year for cleaning bore hole water for the ponds and used a rate of 0.5GPM/sq ft of filter and put in a 500 sq ft filter. I once tried to run the settling pond water through it and it plugged up in a day. Thank God the filter literally blew up, no rebar in the concrete, because it was a constant chore washing the top layer of sand. Even our new sand filter for house use and plant watering needs to be cleaned every 6 weeks. But the water coming from it is clear and tasty.

Municipal water supplies are not cleaning fish poop through their sand filters and I would approach that idea with extreme caution.

rgds

Thanks for the reply. Indeed, suspended solids plug sand filters quickly and I agree that approaching the idea of using a slow sand filter should be approached with caution. A couple of questions. When you pumped your settling pond water into your 500 sq. ft. slow sand filter did it have suspended solids?....and was it these suspended solids that plugged the filter? Also, can you describe the construction of your 500 sq. ft. slow sand filter?

I guess that I'm asking about this because municipal water supply slow sand filters are considered to be a very cost effective way to clean water so long as sufficient land is available for constructing the facility. It might be that a fish pond is too small of a system to take advantage of the efficiencies available with a full on slow sand filtering system...I don't know...but would like to work on this. Your help by explaining your experiences is appreciated.

Chownah

Rather than hijacking Tilapia's biofilter thread I posted a reply to you in the sand filter thread.

rgds

[chownah]

Somtham,

Good idea I guess....I am concerned in that since I want to pursue the idea of using a slow sand filter for cleaning water for intensive fish farming and since the slow sand filter topic has nothing in the title to attract intensive fish farmers that it won't attract much attention and so my input will be limited. Perhaps I can post here to ask questions about how the typical filtration system using bio-media work. Might as well start now: Does anyone have a good link that talks about bio-media and its use in recircution filtration for intensive fish farming? Is a settling pond usually used in recirculating systems and if so does the water exiting the settling pond usually have no suspended solid....as judged by visual obvservations...does it look clear or can you see suspended particles or is it cloudy?

Chownah

[frikkiedeboer]

Somtham,

Good idea I guess....I am concerned in that since I want to pursue the idea of using a slow sand filter for cleaning water for intensive fish farming and since the slow sand filter topic has nothing in the title to attract intensive fish farmers that it won't attract much attention and so my input will be limited. Perhaps I can post here to ask questions about how the typical filtration system using bio-media work. Might as well start now: Does anyone have a good link that talks about bio-media and its use in recircution filtration for intensive fish farming? Is a settling pond usually used in recirculating systems and if so does the water exiting the settling pond usually have no suspended solid....as judged by visual obvservations...does it look clear or can you see suspended particles or is it cloudy?

Chownah

there is plenty of information on the net about biofiltration systems, but i have never found anything you could use which has a formula for waste produced=volume of filter/filter medium/exchange rate/stocking density. this is probably because each system will vary in its efficacy,depending on oxygen supply and bacteria population. the key to any biofiltration system is OXYGENATION- the population of aerobic bacteria you need to use to clean your water need oxygen. the filter medium you use is irrelevant to the equation, as long as it supplies the surface area to keep as much of the bacterial film in contact with as much of the OXYGENATED waste water as possible. sandfilters work well, but if they are used in the first phase of filtration, they will clog very easily. best bet is at least a three chambered system, removing and activating sludge, then passing thru progressively finer filter media. only a single pump can be used if you allow the pressure from the outlet to the first oxygenating stage to spin a paddlewheel system to oxygenate the other stages,too. you do not need the so-called professional plastic media. ordinary granite chips, or broken bits of "yit-daeng" (those small clay bricks with the two holes thru the center, which your local hardware supply will be only too happy to let you have for free) are both excellent media. my personal favourite,-nature's own- is a "vegetable filter". you can try to create your own mini-wetland as one of your filtration stages,or even use a rice-paddy to do the job for you. there is huge scope for running the waste thru a gravel-bed in which vegetables could be grown hydroponically- any vegetation will benefit from the wastes, and help to clean the water ,and will thrive in such a system.

the hydroponics thing is a great way to recoup some of the costs of running the filtration system, and could well be the key to making the whole high density system work in the thai situation. "pak-boong" is one of the water-loving crops that comes to mind as having great potential for one of thes systems. do not forget that a single ton of pla-douk will be producing probably in the region of 50kg per dey of waste,if feeding correctly and this is all great fertiliser for any crop you care to grow.

good luck

frikkie

[Tilapia]

Somtham,

Good idea I guess....I am concerned in that since I want to pursue the idea of using a slow sand filter for cleaning water for intensive fish farming and since the slow sand filter topic has nothing in the title to attract intensive fish farmers that it won't attract much attention and so my input will be limited. Perhaps I can post here to ask questions about how the typical filtration system using bio-media work. Might as well start now: Does anyone have a good link that talks about bio-media and its use in recircution filtration for intensive fish farming? Is a settling pond usually used in recirculating systems and if so does the water exiting the settling pond usually have no suspended solid....as judged by visual obvservations...does it look clear or can you see suspended particles or is it cloudy?

Chownah

Hi Chownah.

The bio-media is needed for break down nitrite and ammonia, depending on your stocking density, that will determent how much media you will need. Up to 50-60kg/m3 bottle-caps with a hole punched in the middle works fine, but above that then the problems start, and it begins to be rather expencive, some of the best bio-media on the market is K1 and they charge 25.000baht/m3 of media, for one of my systems I would need 10m3 of media, 250.000 baht, a fair bit of cash for some plastic rings...

The solids will sink to the bottom in the settlement tank, before the water enter the bio-media, a good idea is to put some screen-filters after the the settlement tank to capture small particles, so that the water there enter the bio-media is as clean as possible. People with the right money often use a drum-filter instead of the settlement tank.

But all this is again depending on your water parameters, the pH, DO, temparature, hardness, salinity, alkalinity. If you can manage to have a high DO and a steady neutral pH, then many of the problems are gone, but if your DO drops to under 3-4, then its getting critical.

There are so many things to consider doing recirculation systems, one guy told me once that it is like "sitting with a live grenate in your hand, the pin is out and you have lost it" It requires 24/7 attention, and generators as back-up. But it is a challenge and it will be the future of fish farming also here in Thailand.

Tilapia.

[chownah]

Tilapia,

Thanks for the reply. I think that your budget is big enough that it is worth at least looking into options. How much room do you have for a water treatment area? Frikkiedeboer's idea about using plants is a good idea...a municipal engineer might call this a 'bio-swale'.

I'm not wanting to sidetrack this thread...so....if anyone knows where commercial bio-media for filters can be obtained please post it here...or if you've got ideas for a substitute.

With the commercial media how do you clean the filter?...backflush? Also, does the usual system oxygenate the water before it goes into the filter?...do you have a link to a website that you think is good at explaining your approach?...this might answer alot of my questions.

By the way....I think I remember Maizefarmer mentioning that he built a water filter using chipped plastice bottles as the filter media. It seems like flat chips would tend to lay flat against each other and thus present less surface area for bacteria to grow on but it might be worth checking into.

Chownah

[Tilapia]

Tilapia,

Thanks for the reply. I think that your budget is big enough that it is worth at least looking into options. How much room do you have for a water treatment area? Frikkiedeboer's idea about using plants is a good idea...a municipal engineer might call this a 'bio-swale'.

I'm not wanting to sidetrack this thread...so....if anyone knows where commercial bio-media for filters can be obtained please post it here...or if you've got ideas for a substitute.

With the commercial media how do you clean the filter?...backflush? Also, does the usual system oxygenate the water before it goes into the filter?...do you have a link to a website that you think is good at explaining your approach?...this might answer alot of my questions.

By the way....I think I remember Maizefarmer mentioning that he built a water filter using chipped plastice bottles as the filter media. It seems like flat chips would tend to lay flat against each other and thus present less surface area for bacteria to grow on but it might be worth checking into.

Chownah

Hi Chownah.

What Frikkie is talking about is a root-zone treatment of the water, and if you have land enough, then it is a good solution, also to create an altenative income, if the bi-product can be sold. But that much space I dont have, so there is only the hard way, I guess, to oxygenate the bio-media is good, it makes the whole process work better, the bio-media is in nets, and when they get to dirty, simply take them out and wash them down, not all in one time, but when needed. The media must have a huge surface-area and still be able to let the water run throug without slowing it down or completly block the flow, I have some samples and I will mail them to you. I have just spoked to a Danish company today, who are doing a bio-reactor and it seems to be very effective, I'm waiting for prices and some specifications.

best regards.

Tilapia.

[Tilapia]

Tilapia,

Thanks for the reply. I think that your budget is big enough that it is worth at least looking into options. How much room do you have for a water treatment area? Frikkiedeboer's idea about using plants is a good idea...a municipal engineer might call this a 'bio-swale'.

I'm not wanting to sidetrack this thread...so....if anyone knows where commercial bio-media for filters can be obtained please post it here...or if you've got ideas for a substitute.

With the commercial media how do you clean the filter?...backflush? Also, does the usual system oxygenate the water before it goes into the filter?...do you have a link to a website that you think is good at explaining your approach?...this might answer alot of my questions.

By the way....I think I remember Maizefarmer mentioning that he built a water filter using chipped plastice bottles as the filter media. It seems like flat chips would tend to lay flat against each other and thus present less surface area for bacteria to grow on but it might be worth checking into.

Chownah

Hi Chownah.

What Frikkie is talking about is a root-zone treatment of the water, and if you have land enough, then it is a good solution, also to create an altenative income, if the bi-product can be sold. But that much space I dont have, so there is only the hard way, I guess, to oxygenate the bio-media is good, it makes the whole process work better, the bio-media is in nets, and when they get to dirty, simply take them out and wash them down, not all in one time, but when needed. The media must have a huge surface-area and still be able to let the water run throug without slowing it down or completly block the flow, I have some samples and I will mail them to you. I have just spoked to a Danish company today, who are doing a bio-reactor and it seems to be very effective, I'm waiting for prices and some specifications.

best regards.

Tilapia.

[chownah]

Tilapia,

This link:

http://cat.inist.fr/?aModele=afficheN&cpsidt=15274199

Talks specifically about,"Three kinds of locally available plastic biofilter media with different configurations (plastic rolls, PVC pipes and scrub pads) were evaluated for their efficiency in organic waste removal from the effluents of an intensive recirculating tilapia culture system. "

It recommends PVC pipes because they are cheaper.

Chownah

P.S. Also found a site that suggested that coconut peel (hulls I guess) made a good biofilter medium for removing nitrogen....which makes sense because you need some carbon available along with the nitrogen for maximum bacterial growth I think...at least this is what you need in a compost pile....and coconut hulls are very porous and are primarily cellulose I think so that would provide the substrate and the carbon...I guess....they weren't too clear on just how this was done.

Chownah

[Tilapia]

Tilapia,

This link:

http://cat.inist.fr/?aModele=afficheN&cpsidt=15274199

Talks specifically about,"Three kinds of locally available plastic biofilter media with different configurations (plastic rolls, PVC pipes and scrub pads) were evaluated for their efficiency in organic waste removal from the effluents of an intensive recirculating tilapia culture system. "

It recommends PVC pipes because they are cheaper.

Chownah

P.S. Also found a site that suggested that coconut peel (hulls I guess) made a good biofilter medium for removing nitrogen....which makes sense because you need some carbon available along with the nitrogen for maximum bacterial growth I think...at least this is what you need in a compost pile....and coconut hulls are very porous and are primarily cellulose I think so that would provide the substrate and the carbon...I guess....they weren't too clear on just how this was done.

Chownah

Hi Chownah.

I saw the data on the link, they were not very specific about the density, except that they called it intensive growing...I think we have to make two catagories here, one for intensive growing, and one for super intensive. Hair-curlers, pvc-pipe, bottle-caps, and many more items, can be used as bio-media, to a certain level, after that level it all goes to a different stage, that require a lot more of the bio-media, and the whole system as such. I would love to increase my density to 75-90kg/m3, with the same electrical cost as I have now, I have seach up and down, but there dont seem to be any short-cuts in this matter.... Swallow the camel...I guess.

Best regards.

Tilapia.

[chownah]

Tilapia,

I don't understand what this means:

I think we have to make two catagories here, one for intensive growing, and one for super intensive. Hair-curlers, pvc-pipe, bottle-caps, and many more items, can be used as bio-media, to a certain level, after that level it all goes to a different stage, that require a lot more of the bio-media, and the whole system as such.

One one hand it seems that you are saying that for higer densities you would just need to increase the size of your filter...this implies that using the same kind of medium (Hair-curlers, pvc-pipe, bottle-caps) would work if you just got more of them. On the other hand you say that these media only work "to a certain level, after that level it all goes to a different stage" which implies that these media can not function at the level required.

So...I'm confused. Do these media work at the super intensive level and you just need more of them?...or is there something about the requirements of the super intensive level that these media can not provide?

As to the level of intensity of the study at the link: The link is just an abstract of a study....the reference for the complete study is below. I'm reasonably sure that if you obtain a copy of the full study it will detail the degree of intensification they were working with and probably describe the media they used in detail.

Aquacultural engineering (Aquac. eng.) ISSN 0144-8609 CODEN QEND6

2003, vol. 29, no3-4, pp. 139-154 [16 page(s) (article)] (1 p.1/4)

Chownah

[Tilapia]

Tilapia,

I don't understand what this means:

I think we have to make two catagories here, one for intensive growing, and one for super intensive. Hair-curlers, pvc-pipe, bottle-caps, and many more items, can be used as bio-media, to a certain level, after that level it all goes to a different stage, that require a lot more of the bio-media, and the whole system as such.

One one hand it seems that you are saying that for higer densities you would just need to increase the size of your filter...this implies that using the same kind of medium (Hair-curlers, pvc-pipe, bottle-caps) would work if you just got more of them. On the other hand you say that these media only work "to a certain level, after that level it all goes to a different stage" which implies that these media can not function at the level required.

So...I'm confused. Do these media work at the super intensive level and you just need more of them?...or is there something about the requirements of the super intensive level that these media can not provide?

As to the level of intensity of the study at the link: The link is just an abstract of a study....the reference for the complete study is below. I'm reasonably sure that if you obtain a copy of the full study it will detail the degree of intensification they were working with and probably describe the media they used in detail.

Aquacultural engineering (Aquac. eng.) ISSN 0144-8609 CODEN QEND6

2003, vol. 29, no3-4, pp. 139-154 [16 page(s) (article)] (1 p.1/4)

Chownah

Hi Chownah.

Did you get the mail I send you, with the bio-reactors ?

As you say, why not add more of the pipes, hair-curlers and bottle-caps, yes it can be done, if there is room for it, but it is not the optimal solution, if you want to use the system to the full capasity, there are many factores to take in cosideration specially when (as I) want to push the limits, each case is not the same, it depends of the water-parameters that you have in the area you are in, so it is not possible to take a study from the internet and copy it to your own farm, and think it will work, it wont, but it can be use as a guide-line, and from there you are on your own. The stage that I am in now is between rural intensive fish-farming and super intensive farming on commercial scale, and to get there takes more investment in equipment, and I am trying to cut corners, that was the reason for starting this forum, to see if there was anybody who were doing the same kind of farming.

best regards.

Tilapia

[macan]

I think the issue is that Tilapia wants to increase the surface area available for biological contact (bio-filtration) within an existing filtration vessel/tank (space and tank construction costs are a factor). At the moment he is using cheap, readily-available recycled or adapted materials, but it looks like he may have to buy the dedicated substrate balls or sheet materials that are ridiculously expensive. He has taken his system to the maximum capacity of the existing biofilter substrate/media (limited by surface area for growth of the necessary biological gunk) and wants to go further which requires complex shapes with high surface area to volume ratio.

As i understand it he wanted to know if anyone has a solution that will allow him to maintain water flow and operating costs at, or near the present levels. I don't know of any ingenious backyard solutions and doubt if anyone is rearing tilapia at the levels he is in Thailand (or elsewhere in Asia). There used to be an Italian guy working for Thai Gypsum who was into recirc but I'm not sure if he is still around; I'll try to track him down.

[Tilapia]

I think the issue is that Tilapia wants to increase the surface area available for biological contact (bio-filtration) within an existing filtration vessel/tank (space and tank construction costs are a factor). At the moment he is using cheap, readily-available recycled or adapted materials, but it looks like he may have to buy the dedicated substrate balls or sheet materials that are ridiculously expensive. He has taken his system to the maximum capacity of the existing biofilter substrate/media (limited by surface area for growth of the necessary biological gunk) and wants to go further which requires complex shapes with high surface area to volume ratio.

As i understand it he wanted to know if anyone has a solution that will allow him to maintain water flow and operating costs at, or near the present levels. I don't know of any ingenious backyard solutions and doubt if anyone is rearing tilapia at the levels he is in Thailand (or elsewhere in Asia). There used to be an Italian guy working for Thai Gypsum who was into recirc but I'm not sure if he is still around; I'll try to track him down.

Hi Macan.

Sometimes it makes life alot easier when you are a native English person, to put the right words on the paper, not like a back-wards Dane like me. Thanks for the help Macan.

Tilapia.

[chownah]

Well, if the goal here is to use the same filter vessel and upgrade the medium used then for sure sand is not what you want.

Chownah

[frikkiedeboer]

Tilapia,

This link:

http://cat.inist.fr/?aModele=afficheN&cpsidt=15274199

Talks specifically about,"Three kinds of locally available plastic biofilter media with different configurations (plastic rolls, PVC pipes and scrub pads) were evaluated for their efficiency in organic waste removal from the effluents of an intensive recirculating tilapia culture system. "

It recommends PVC pipes because they are cheaper.

Chownah

P.S. Also found a site that suggested that coconut peel (hulls I guess) made a good biofilter medium for removing nitrogen....which makes sense because you need some carbon available along with the nitrogen for maximum bacterial growth I think...at least this is what you need in a compost pile....and coconut hulls are very porous and are primarily cellulose I think so that would provide the substrate and the carbon...I guess....they weren't too clear on just how this was done.

Chownah

the point that everybody seems to be missing here is that, no matter which filter medium you use,without OXYGENATION the AEROBIC BACTERIA-( the one we are trying to cultivate, and this bacteria is heavily dependent on oxygen to do its job correctly ), will die. the idea is to have as much of the bacteria exposed to as much of the BACTERIA-not just the media- as possible.

almost all the media suggested by posters here are good. sure, the larger the surface area the more bacteria can be accommodated,and the more water can come into contact with the bacteria, and this is very important but oxygenation is critical.

you will find big paddlewheels on some of the rivers,canals and ponds in thailand.(i am not talking about the ones they use in the shrimpfarming industry). these are used to stimulate the growth of aerobic bacteria to clean up the contaminated water. this system i have seen all over-from the canals in korat to a huge one in the pond in lumpini park,bankok, and they work in the absence of commercially available filter media,although they would obviously be more effective if they did use media.

it is also very important to use a system comprised of different,seperate chambers.as,depending on nutrient load,the first stage can change over between nitrification and denitrification and back. forget the expensive commercially available medium-each supplier claims his is the best and what is best for your situation is the one which does the job for you and fits your budget and available space. even professional filter suppliers disagree on which system is best- some push the trickle tower concept and others tell you this is not a good system and that a three chambered system is necessary.

i suggest you experiment with what is available. the bottlecaps,broken pvc pipes, sand,stone,broken pottery shards etc all will work well. coconut husk will probably be good too, but most media seems to be made of inorganic material , although i read an article claiming that sphagmum moss had tested as the finest medium available.

good luck,

frikkie

[Somtham]

Sometimes it makes life alot easier when you are a native English person, to put the right words on the paper, not like a back-wards Dane like me. Thanks for the help Macan.

Tilapia.

Your English is fine. I wish I could write a second language as well as you do. Welcome to TV. You need to understand that there are certain members that will challenge everything that anybody writes. Take it with a grain of salt and move on.

rgds

[Somtham]

Did you get the mail I send you, with the bio-reactors ?

As you say, why not add more of the pipes, hair-curlers and bottle-caps, yes it can be done, if there is room for it, but it is not the optimal solution, if you want to use the system to the full capasity, there are many factores to take in cosideration specially when (as I) want to push the limits, each case is not the same, it depends of the water-parameters that you have in the area you are in, so it is not possible to take a study from the internet and copy it to your own farm, and think it will work, it wont, but it can be use as a guide-line, and from there you are on your own. The stage that I am in now is between rural intensive fish-farming and super intensive farming on commercial scale, and to get there takes more investment in equipment, and I am trying to cut corners, that was the reason for starting this forum, to see if there was anybody who were doing the same kind of farming.

best regards.

Tilapia

OK, so a I have to ask a maybe stupid, non-ecological question. Why don't you just run the water through your existing system and then dump it and pump new water rather than recirculating?

And if you still want to recirculate with a cheap biofilter I have an idea. After a few Changs tonight I thought, "why not pens". Pens are a dime a dozen in Thailand and they have a housing (biofilter), a spring, and ink cartridge, and a open/close mechanism. Why not find a Thai factory that makes pens and buy their reject housings? Lots of surface area and still a good flow through for water. Have some extra cheap labor around? Cut the nose off to make it the same diameter as the rest of the barrel. More labor? Get some super glue and bond them together in a criss cross pattern to make those expensive biofilters that nobody in Thailand can afford. Make up some blocks that are easy to handle and clean.

What do you think? Maybe you can search the net to find the factories and then have the missus call the factory for pricing on reject barrels.

rgds

[Tilapia]

Sometimes it makes life alot easier when you are a native English person, to put the right words on the paper, not like a back-wards Dane like me. Thanks for the help Macan.

Tilapia.

Your English is fine. I wish I could write a second language as well as you do. Welcome to TV. You need to understand that there are certain members that will challenge everything that anybody writes. Take it with a grain of salt and move on.

rgds

Hi Somtham.

Thanks for the nice words, I do get your point, and I promise that I wont lose any sleep over those certain members.

The idea with the pens, might work, if they are used in a trickle filter, it will take some work to put it together, but it will be cheaper than the original stuff, I will do some reseach. Do take a few more Changs, you seem to get some good alternative solutions from them.

Rgs

Tilapia.

[chownah]

Tilapia,

I don't lose any sleep over those certain members either.

Have you decided then that your existing filter vessel is not itself going to give you what you want and you are considering augmenting it with a trickle filter?...possibly using filter media made from defective pen barrels?

Chownah

[Somtham]

Hi Somtham.

Thanks for the nice words, I do get your point, and I promise that I wont lose any sleep over those certain members.

The idea with the pens, might work, if they are used in a trickle filter, it will take some work to put it together, but it will be cheaper than the original stuff, I will do some reseach. Do take a few more Changs, you seem to get some good alternative solutions from them.

Rgs

Tilapia.

So why not just "dump" the water and pump new water rather than expanding your biofilter?

One more thing. I met a guy at a "wat bote opening ceremony" in Korat who owns a factory in BKK and manufactures those cheap cigarette lighters for export to the tune of ~20M per month as I recall. So he has a number of injection molding machines and not sure what else he is making. He may have some ideas and contacts for the real biofilters and/or ideas for a do-it-yourself filter. Maybe I'll take him up on his offer for a factory tour and a round of golf!

rgds