Pond Construction

[krayner]

I put this on the general section but it was suggested that I might try here as well, I might as well put it in the farming section to. One of the replies did suggest some liner suppliers and these seem to come in very large sizes for lakes on golf courses.

Does anybody here know about building ponds for ornamental fish. I was intending to build a pond about 25 feet in diameter with a concrete base and bottom drains then concrete block walls and a proper filter system.

However the wife has got involved and built me this monster. Basically she went over to Thailand to supervise the completion of a building project in Ranong and they needed, well she said they needed, I am not convinced, to do some landscaping and leveling of the ground.

So on the basis that they had an excavator on site and they needed the material for the landscaping they built this huge pond.

It is full of water now but after a few months of the dry season I can't see there being much water in it.

It stikes me as being far too big to build in concrete and blocks, especially as I know very little about concrete so I guess I will need a liner.

Do they have Butyl rubber in Thailand and how much will something that size cost me? If I use butyl I can still put in the bottom drains and build the filter.

The other alternative is that i turn it into a swimming pool. I am also a bit concerned about the proximity to the sea. I don't know if the tide ever comes up that high, there has been no sign that it does.

Any ideas.

[Maizefarmer]

You have a problem - that pond is right up at the coast and the soil it is dug into is not a clay base type i.e. your pond will dry out in the dry season unless it is lined - with concrete or whatever else - rubber or even plastic sheeting. Plastic sheeting with soil on top is your cheapest bet.

Something you need to keep in mind - proximity to the sea - the water in the pond is going to require replacement on a regular basis as the salintity is going to build up over time which will impact on the ornamental fish you keep in it. So next question: do you intend to have a throughflow into/out of this pond?

The other thing to keep in mind: unless you line it will for ever stay muddy.

You could throw concrete - but you will need to compact the base first and throw down a hardcore as the ground underneath is going to subside a lot - so a reinforce mesh in the concrete is also required. Remember to add a waterproofing compound to the concrete mix.

How would I do this pond:

- compact base

- throw down crushed hardcore (building waste to small stones or gravel will be all fine)

- throw down some dry pack (basically a semi dry/semi wet cement mix) - gets the labourers to

beat it all down to the shape and profile you want.

- allow it to set for a day or so

- throw down a plastic liner

- 4 x 4 steel reinforcing mesh on top of the liner

- throw down your concrete.

- let it set and spray with water everyday for about 10 -12 days to ensure it cures properly.

Makew sure the rim/edges of the pond are a good 6" thick and has a 2" x 2" mesh in it - else you can be sure it is going to crack with people walking around the side of the pond - and if the edge cracks then it will propergate down the side of the pond allowing the water to seep between the liner and the concrete base.

You can use butyl rubber but it aint cheap stuff in Thailand - the above would be cheaper and stronger. For sure if you just apply a plastic base it is going to get torn at some point.

Filter system - well you can construct that yourself - and yes, it will be required if you want to keep that water clean - preferably a biological filter. You can use anything for as a filter media cut up plastic coke bottles are great - will just take some time for the system to mature. My concern would be keeping the water clear versus how much you have to replace and the energy cost to keep the pimp going. Work on around been able to circulate the entire volume at least 2 every 24 hours.

Nice thing about cement, sand, hardcore and other building materials in Thailand is that they are really cheap and I cant see it costing much more then about Baht 12K - 15K to do all the above - excepting the cost of the pump.

Tim

Edited October 12, 2006 by Maizefarmer

[krayner]

You have a problem - that pond is right up at the coast and the soil it is dug into is not a clay base type i.e. your pond will dry out in the dry season unless it is lined - with concrete or whatever else - rubber or even plastic sheeting. Plastic sheeting with soil on top is your cheapest bet.

Something you need to keep in mind - proximity to the sea - the water in the pond is going to require replacement on a regular basis as the salintity is going to build up over time which will impact on the ornamental fish you keep in it. So next question: do you intend to have a throughflow into/out of this pond?

The other thing to keep in mind: unless you line it will for ever stay muddy.

You could throw concrete - but you will need to compact the base first and throw down a hardcore as the ground underneath is going to subside a lot - so a reinforce mesh in the concrete is also required. Remember to add a waterproofing compound to the concrete mix.

How would I do this pond:

- compact base

- throw down crushed hardcore (building waste to small stones or gravel will be all fine)

- throw down some dry pack (basically a semi dry/semi wet cement mix) - gets the labourers to

beat it all down to the shape and profile you want.

- allow it to set for a day or so

- throw down a plastic liner

- 4 x 4 steel reinforcing mesh on top of the liner

- throw down your concrete.

- let it set and spray with water everyday for about 10 -12 days to ensure it cures properly.

Makew sure the rim/edges of the pond are a good 6" thick and has a 2" x 2" mesh in it - else you can be sure it is going to crack with people walking around the side of the pond - and if the edge cracks then it will propergate down the side of the pond allowing the water to seep between the liner and the concrete base.

You can use butyl rubber but it aint cheap stuff in Thailand - the above would be cheaper and stronger. For sure if you just apply a plastic base it is going to get torn at some point.

Filter system - well you can construct that yourself - and yes, it will be required if you want to keep that water clean - preferably a biological filter. You can use anything for as a filter media cut up plastic coke bottles are great - will just take some time for the system to mature. My concern would be keeping the water clear versus how much you have to replace and the energy cost to keep the pimp going. Work on around been able to circulate the entire volume at least 2 every 24 hours.

Nice thing about cement, sand, hardcore and other building materials in Thailand is that they are really cheap and I cant see it costing much more then about Baht 12K - 15K to do all the above - excepting the cost of the pump.

Tim

That is very interesting, I have printed this to keep it for reference. I had initially thought of building in concrete but I was going to keep it to about the third of the size of this. Given the cost of labour and building materials verses a liner then maybe concrete would be the way to go. I suppose as a last resort if it didn't work would to be put a liner on top of the concrete or fibre glass but I know that isn't cheap and for that size would be very expensive.

I just have a few questions. what is the purpose of the liner under the concrete mesh. When constructing the sides would they have to be shuttered or if the slope is not too great would the concrete remain in place one poured. How steep can the sides be before the poured concrete just finishes up in the bottom of the pond.

In the UK they use plastic fibres mixed in a very strong cement render to skim the surface of a concrete or block pond to make it waterproof. The high cement content gives the water proofing and the fibres stop it cracking but again that is in much smaller ponds than this.

The advantage to me of doing it in concrete is that I could raise it up a bit by building a retaining wall at the front. At the back is high ground anyway. That would help if there was ever a very high tide.

It would also be easier to build in some sort of waterfall feature at the back using the high ground. Some of the storm water runoffs from the high ground falls here so I was going to try and utilise that in some way. I had intended to put in a filter so every time I travel out I am putting plastic bottom drains for koi ponds in my luggage.

I must have about 5 out in Thailand at the moment so later this year I should be able to get that up to 7.

[Maizefarmer]

It's for koi is it - remember the deeper the pond the better (shape) koi will develope/grow into - as you proberbly know, they are meant to be viwed from above. You want that - the filtered water coming in at the shallow (where it will be moving and stay cool) and the deeper end down by where it outlets to the filter system.

Why plastic between the layers?

Fill the pond up with water and you are going to have around 100 tons of weight pushing down. In the dry season with all the moisture in the soil around the pond gone, it will move and move a lot it will (wait and see). If the base cracks then its cracked right through. You really want 2 seperate layers that can move and flex seperately over a surface that size.

BUt I am making some assumptions here, mainly that this is not going to be built to swimming pool standards. However if you are going to down that route and to the extent of making the base a good 6" plus thick, then no it wont be required.

Yes you can go round to any yacht builder in Phuket and ask him where he buys his fiberglass chopped mat - and use that mixed in with the concreate - add a "plasticiser liquid" (Fairy washing up liquid is great) - stops the chopped glass fiber strands rolling into a ball when you throw it all into the mixer with the cement.

Tim

Edited October 14, 2006 by Maizefarmer

[Naam]

i have a similar monster of pond for kois but built with steel-reinforced concrete like a pool. quite some problems since inception two months ago but not with the structure.

-first problem was that the clown of subcontractor who provided the plants for the pond used normal soil instead of special clay or stones in the plant pots. soil dissolved and i had a muddy brew

had to pump out the pond, clean it thoroughly and wash out all soil from plant roots.

-another problem is the development of green algae. have installed a normal pool filtration system (sandfilter not D.E.) with a 1.2HP pump which obviously cannot cope. another 1.2HP pump is just for aeration (waterfall).

lately i see some small improvement and i can see my fish up to a depth of ~ 50cm, however water is by far not as clear as in my german pond which had no filtration system at all.

experts are telling me it can take several months till an ecologically balanced climate develops, lotus are covering at least 50% of water surface till i can expect much clearer water.

[bkkmadness]

-another problem is the development of green algae. have installed a normal pool filtration system (sandfilter not D.E.) with a 1.2HP pump which obviously cannot cope. another 1.2HP pump is just for aeration (waterfall).

Is the problem not so much green algae growing on the sides of the pond, but more a green water problem? It does take a pond a while to settle down, and the more plants you get in there the clearer the water will become as the plants eventually will starve the algae for nutrients. Elodea plants are useful for this. Koi will of course see your new plants as a nice little snack so you may want to have these plants set off to one side in the pond where the Koi can't get at them. You can have your filter running into a smaller pool first before entering the pond and have the plants in there for example.

I'm not sure if you can buy barley straw here? Often people used to float this in a bundle in the pond, or weigh it down in the water to help clear green water problems. Its a bit of an old school solution to the problem and doesn't always work but it is worth a try. Alternatively as a last resort perhaps it could be worth installling a UV filter.

[Maizefarmer]

No. 1 - keep sand out of the pond - yes, the contrcater didnt know his arse from his albow.

No 2 - in Thailand you realy need to get a bio filter up and running - it should have a volume of around 2 - 5% of the pond volume and the throughflow should be around 2 times the pond volume per 24 hours. In other words, its not how many times you circulate the water but how well (i.e. how much time) you can give it to circulate through the biofilter - the longer the better.

I no nothing about a straw bail in the pond so I can't comment one way or the other

You can use anything as a media in the biofilter - I use old plastic coke bottle - cut up they provide loads of surface area.

But you must have fish in the pond - the filter will not mature properly if their is no biological load, and the bio -load in the filter is proportional to the amount of fish in the pond.

Takes time, but will be the end of your green water problem.

Tim

[Maizefarmer]

A good simple and practical insight to building your own biofilter can be found on:

http://home.netcom.com/~larry_l/filter_101.htm - cut and paste in the address bar.

I have an issue with biologists who argue for fast through - flow. I guess from their discipline point of view their argument is right, however my discipline (ag engineering) argues for efficiency and practicaility, and I assure all, a flow 25% of that suggested in any biofilter design will achieve just as good results.

KRAYNER - you may well wish to give thought to using a solar panel to drive the pump(s)- 2 x 50watt submersible aquarium pumps will give you about 10 - 12 000 litres p/hour with zero energy costs and will run the whole year round (with night time running done on one pump off a car battery charged during the day).

Tim

Edited October 14, 2006 by Maizefarmer

[Naam]

"Is the problem not so much green algae growing on the sides of the pond, but more a green water problem?"

that's exactly the case "fishkeeper" and it's definitely green algae. the pump capacity is around 300 liters/hour but i have to backwash the filter every two hours as it gets clogged. trying to add some diatomite to the sandfilter to increase filtration efficiency (as i do sometimes with my pool) was a flop. filter gets clogged after a few minutes only.

what i don't understand is the very high pH-value >9 of the pond water as my wellwater (which feeds the pond) is rather acidic with a pH of 6.2-6.5. i am hesitating to bring the pH with acid down as i don't know how this will affect my fish. i read that drastic changes in pH might hurt the fish.

most probably i have to construct an additional bio-filter (suggested by Maizefarmer) although it is not clear to me (yet) how it works.

the good news is that after cleaning the pond and removing most of the soil the water is slowly getting clearer every day.

[Naam]

"you may well wish to give thought to using a solar panel to drive the pump(s)- 2 x 50watt submersible aquarium pumps will give you about 10 - 12 000 litres p/hour"

-----

i humbly beg to differ "Maizefarmer" as a 50W pump is not capable to move 5-6.000 liters an hour. even without any filtration and head resistance a 50W pump can move only a fraction of that volume.

*****

"No 2 - in Thailand you realy need to get a bio filter up and running - it should have a volume of around 2 - 5% of the pond volume and the throughflow should be around 2 times the pond volume per 24 hours."

------

the volume of my pond is around 98 m3 which would require a bio filter of 2-5 m3 and a pump capacity of >8.000 liters per hour (pumping around the clock) which could be achieved with a ½HP (~350W) pump. but searching the net and reading for hours a lot of bla-bla i still have not the faintest idea how a bio filter works AND how it should be constructed

Edited October 15, 2006 by Dr. Naam

[teletiger]

"Is the problem not so much green algae growing on the sides of the pond, but more a green water problem?"

that's exactly the case "fishkeeper" and it's definitely green algae. the pump capacity is around 300 liters/hour but i have to backwash the filter every two hours as it gets clogged. trying to add some diatomite to the sandfilter to increase filtration efficiency (as i do sometimes with my pool) was a flop. filter gets clogged after a few minutes only.

what i don't understand is the very high pH-value >9 of the pond water as my wellwater (which feeds the pond) is rather acidic with a pH of 6.2-6.5. i am hesitating to bring the pH with acid down as i don't know how this will affect my fish. i read that drastic changes in pH might hurt the fish.

most probably i have to construct an additional bio-filter (suggested by Maizefarmer) although it is not clear to me (yet) how it works.

the good news is that after cleaning the pond and removing most of the soil the water is slowly getting clearer every day.

Might I suggest that the high ph comes from the concrete used in construction. The pond needs to be aged. A pond that size might take 6/12 months before the concrete stops leaching lime into the water.

Adding a population of snails and catfish will help with the green water. Patience is the keyword here. I'm sure that in a years time your pond will look wonderful.

Regards

Edited October 15, 2006 by teletiger

[Beachbunny]

-another problem is the development of green algae. have installed a normal pool filtration system (sandfilter not D.E.) with a 1.2HP pump which obviously cannot cope. another 1.2HP pump is just for aeration (waterfall).

Is the problem not so much green algae growing on the sides of the pond, but more a green water problem? It does take a pond a while to settle down, and the more plants you get in there the clearer the water will become as the plants eventually will starve the algae for nutrients. Elodea plants are useful for this. Koi will of course see your new plants as a nice little snack so you may want to have these plants set off to one side in the pond where the Koi can't get at them. You can have your filter running into a smaller pool first before entering the pond and have the plants in there for example.

I'm not sure if you can buy barley straw here? Often people used to float this in a bundle in the pond, or weigh it down in the water to help clear green water problems. Its a bit of an old school solution to the problem and doesn't always work but it is worth a try. Alternatively as a last resort

perhaps it could be worth installling a UV filter.

Our pond is filled from the canal at the back of our property. We also have an outlet to release water back into the canal.

After initially redigging the pond we had a terrible algae bloom. After research on the internet (and to my knowledge there is no barley straw in Thailand, but that is only for certain types of algae) we filled the pond totally with water hyacinth. Didn't take long at all, maybe a week and the water was clearing up. We gradually reduced the water hyacinth and added local water lilies that the fish don't seem to bother.(they ate all the fancy water lilies) and no problems since. Now mostly lilies and just a small amount of hyacinths still in there.

Beachbunny

[Naam]

"Might I suggest that the high ph comes from the concrete used in construction."

that sounds quite logical "teletiger" but the pH went up 3 points during the first day of refilling. can it happen that fast?

[Naam]

"Patience is the keyword here. I'm sure that in a years time your pond will look wonderful."

thanks "teletiger", you made my day!

another question for the experts. today, shortly after it got bright, i noticed a (rather) small heron flying away. when i fed my fish they took nearly 10 minutes to go after the food whereas they normally flock within a minute to the area where i feed them. they seem having been scared by the bird.

i have hardly seen any birds in this area besides common sparrows and those birds with the yellow beaks which seem to be all over. is there a reason for the lack of birds?

[Naam]

"we filled the pond totally with water hyacinth"

from where can i get water hyacinth "beachbunny"?

[Maizefarmer]

Bio Filters:

www.shooterdog.com/biofiltr.htm - a good DIY page with good explinations

www.lagunakoi.com/html/Filter_Systems.html - another very good page

http://www.azponds.com/filters.htm - coimmerically avaliable biofilters.

With respect, I work with pumps for a living, the figures were off the top of my head based on experiance and a desire to share my expriance with you, but if you wish to hold me to the book for accuracy, having now spent 3 minutes on the nett to find the specs of the 2 pumps I use in my koi pond: Eheim 1262 @ 80 watts pumping just under 4000 litre p/hour each.

Call me a BXXXXXXXXXR for 30 watts and around a thousand litres - which in the case of your pond with a bio filter and an effective negative NPSH (i.e. no suction or discharge head of any value - which is what you will have - the above is quite practical and realistic (you could take it one step further and run the inverter at say 100 -110 Hertz - that will give you the rpm to pump 5000 - 6000 litre per hour). For a guess off my head, the figures were fine - but by all means we can calculate them down to a perfect number if need be and you will see that 50 watts can give you 5 - 6 kilo litre an hour.

I was trying to keep it simple and practical - but okay, lets move on, to try and put this all into a context that you can use & apply easily.

If you look through the webpages I have linked (actually you will have to cut and paste as I havent got a clue how you set it up to click and go straight to the page) it will give you a fair insight into what a bio filter does. To cut a long story short (and to keep it simple) it is to a fishtank what a sewerage farm is to domestic waste/toilet water i.e. it uses biological conversion processes to consume/eat up/use and convert the organic waste produced by the fish and any other organic material (e.g. leaves, bugs) into energy to sustain the bacteria that grow in the filter

The key to the succesfull working of a bio filter is a surface area proportional to the volume and throughflow from and of the main pond. - and the only way to that in a confined area is to throw something into the filter to increase the surface are that the bacteria can grow on and be supported by (anything really - pieces of plastic are great because they will not decompose).

So why does this or cant it occur in the main pond?

Well actually it does to a limited extent - but not anywhere near as much as it is required to because:

- insufficient surface area for the bacteria (it would work if you filled your pond up wish empty coke

bottles or old sponges/scouring pads - anything that provides a large surafce area for its given

volume - but that would look unsightly, so you make a seperate tank).

- water flow - the water needs to keep moving over the media that is used for the bacteria to grow

on, as the bacteria require a constant input flow of "bad water" to feed off - and lots of surface movement in your pond (which is required for oxygenation) will disturb the surface so much you will not be able to view the koi clearly.

- light levels - depending on how sophisticated you want your bio filter to be, you will want a part of

the biofilter to not have sunlight on it, as the sunlight will kill the bacteria feed off the dirty water (and that would mean covering your pond - no point in that)

Inn effect its just not practical to cover your pond to keep the light out (you wont be able to see the fish) , to always have the water moving at the surface (koi as you know are best viewed in still water from above), and its just not going to look good if the pond is stuffed full of empty bottle as well.

At a chemistry level the bacteria which breed in the biofilter conditions consume all the nitrates which accumulate in the pond as the fish waste, food watse and other organic waste such as leaves and bugs, breaks down - returning to the pond water that has none of the organic material in it that causes it to go green or which supports the development of green alge.

A biofiler is a natural proces i.e. the bacteria will start growing by themselves automatically as soon as the pond water starts been pumped through the filter. It may well be a good idea to throw some cheap fish intot he water for about 2 - 3 weeks before you put in your prize koi, along with a handful of leaves - this will proivide a biological load to helpt the biofilter mature quicker so that by the time you come round to putting your fish into the pond, the bacteria are up and running so to speak and doing the job they are wanted for. Its important then to keep the water moving through the filter - which is why I suggested a solar panel - because if the water stops moving for any length of time a lot of the bacteria will/can die, leavin gyou with a filter that is not doing a complte job. It is also important to keep a biological load in the tank - take all the fish out of the pond and the bacteria will dies off as the waste level drops proportionatly and in turn the food avalible for the bacteria also then drops.

In summary the 2 work hand in hand - you can go to great lenbgths to make a very sophisticated filter or you can keep it simple. The 2 basics (all that is really require - anything else added is a trimming): water flow and as much surface area as possible - just stuff as much chopped up plastic bottles or whatever you decide to use as you can into the filter compartment designed to hold it. Extra compartments like acomparyment for settling, a compartment for activated charcoal and a uv light - great additions but not essential.

Anbd lastly - NEVER NEVER EVER EVER clean a bio-filter or the plastic you use to create the surface area - NEVER. clean it will be to destroy it.

Good luck and feel free to ask for more info - I'm technical/practical guy, I am sure there are others who can offer a far better insight into the biology of all this, which is not my cup of tea.

Tim

I put the clickable links in for you RC

Edited October 17, 2006 by RamdomChances

[Naam]

BIG thanks "Maizefarmer"! your posting war more informative than a dozen websites i read and tried to understand without any success. what confused my especially were the empty coke bottles and plastic remnants which in my mind had no relation to anything that starts with "bio" on the contrary.

i will digest your lesson and i hope you don't mind if i bother you with additional questions.

p.s. i suggest we discuss pump capacities and their power consumption over a good bottle of wine (or two).

[RamdomChances]

I've split the slow sand filter bit's into there own thread

[Maizefarmer]

BIG thanks "Maizefarmer"! your posting war more informative than a dozen websites i read and tried to understand without any success. what confused my especially were the empty coke bottles and plastic remnants which in my mind had no relation to anything that starts with "bio" on the contrary.

i will digest your lesson and i hope you don't mind if i bother you with additional questions.

p.s. i suggest we discuss pump capacities and their power consumption over a good bottle of wine (or two).

Ooooops, do not like the sound of this ............. at the end of which you will take the bottle and smack me on the head! I'll bring along a bottle of milk, to retaliate with - joking.

Yup - more than happy to meet up sometime, things are now starting to unwind this end at get quiet now - the years hard work is over and I'll have a load of time on my hands as from the end of this month onwards thru to Jan.

I am in the UK for 2 days from 26 - 28 October and then in Germany till 1 November (agriculture show) - we can meet up in the UK if you wish (that is where u r?)

PM me your email address.

Best Regards

Tim