Fish Pond Pump ( What Size ? )

[pop3]

I have a fish pond 190cm x 130cm x 70cm. it is shaded from direct
sunlight by an asbestos roof. There are about 7 goldfish and a catfish
in the pond, I have no pump of filtration so the water starts to go green in about 4 or 5 days then after about 14 days you can no longer see the fish.

Can anybody give me an idea of what size pump I would need to push enough
water into a filter to keep the water clean ? I do not want to go too
big on the pump but I think if the pump is too small it will not move
enough water ?

Thank you in advance for any information you can provide regarding a pond of this size.

[canuckamuck]

Really I think you could get away with an 80 watt pump, it would probably move 4000 liters an hour, which is twice your volume. But what you really want is a UVpump, which is a type of pump with a UV light inside it which zaps the algae on the way through.

This will keep your water from going green, but it will be hard on your beneficial bacteria too. You should look into biological filter setups to deal with the waste materials.

Edited March 20, 2013 by canuckamuck

[wackysleet]

If you keep the UV lights as a seperate unit after the pump then there will be no affect on the bio filter if you even have one.

No pump or filter will get rid of algae but putting a lot of water plants will help because plants will use the nitrate in the pond.

David.

[pop3]

Thank you for your help, I did see a pump today that was 4,500 liters
an hour and wondered if that would be about right, also I have tried
water plants in the past but the fish would dig them up in next to no
time, what do you think about putting plants in and netting them off
with fine wire so the fish can not get to them ?

[wackysleet]

Pop3.

Plants can be put into fairly large pots and then put some large stones on top and that will help with the fish rooting around or you can place the pots with the rim just above the water level.

Your pond does not contain koi carp which would definitely need a filter at least 25% of the pond volume unless you have a very good through put of water through the filter, pond water with koi should have a total pond turnover ideally every two hours but for goldfish that's not necessary.

I would go for a pump that will pull the water over the filter thus stopping larger parts such as leaves from blocking the pump. but if you want a detailed set up then PM me and I will draw up what you need with the correct pump size.

David.

[canuckamuck]

If you keep the UV lights as a seperate unit after the pump then there will be no affect on the bio filter if you even have one.

No pump or filter will get rid of algae but putting a lot of water plants will help because plants will use the nitrate in the pond.

David.

A UV filter of the correct size will get rid of green water, because that is what they are for. But yes the UV filter will not get rid of algae that is attached to surfaces.

A pump its own is not a complete answer, moving water will still stay green, and it is difficult to mechanically remove green water. Plants help because they compete with the algae in the green water.

Wackysleet, please feel free to post you solutions here for all to see, as there are other people you may help at the same time.

[pop3]

Thank you everyone for your help, first off today I am going to buy the
4500 litres per hour pump and will run it through a filter, I will
change the water in the pond first therefore starting with clean water, I
will post here again in a few days as to what condition the water is in, in the mean time I will look into UV light options.

[wackysleet]

Canuckamuck.

I think your second post is at odds with your first post in as much as you quite rightly point out that a UV pump will destroy any and all bacteria in a filter if placed within the filter body. Placed after the discharge pipe but before the water re;enters the pond is the way to go.

I think what you mean by algae sticking to the sides of the pond and not being removed through the pump/filter is actually blanket weed, a dark green plant like growth akin to cotton wool, this will do no harm and will not contribute to making the water green but will in fact be a source of food for some fish

We discussed this problem on here about 3years ago with a lot of opinions, some very good ideas and some totally impractical, my advice is based on my experiences with my pond of apprx 8,000gallons containing about 100 Koi with 25 fish averaging 70cm with the remainder of various sizes from 20cm.

My ponds water was crystal clear and could easily see a 1 baht coin on the floor at a depth of 4'-0" apprx 135cm, I posted pics showing my pond/fish and water. As the saying goes. The proof of the pudding is in the eating".

In my filter installation twin pumps were placed in the last chamber of 3, drawing water over 3 filters of various density, the water then being pumped via 2 pipes with 2 large inline UV lights in each return pipe, 1 pipe back to the pond the other feeding a series of 3 concrete ponds eventually forming a series of waterfalls, these 3 concrete ponds apprx size 5'-0"x 2'-0" x 1'-0" deep were filled with varios plants thus ensuring that virtually all algae feeding nitrate was removed .

A good filtration system is best understood with pics and instructions, not so easy to explain to a novice but easily achievable at minimal cost.

Your quote of 4,000 litres being twice as much as pop3s pond volume is correct. For those posters wishing to calculate water volume the maths are simple, length x width x depth will give you cubic feet then x 6.25 = gallons, I will let you work out the litres {English gallons not USA gallons}.

For a circular pond or other vessel, work out the square radius of the pond, the depth and pi, which is 3.142;.

To work out the square radius of the pond by multiplying half the diameter feet by half the diameter feet.

Multiply your answer by the depth of the pond feet and then multiply by 3.142 {pi}, this will give you the cubic capacity in feet.

Then multiply the answer by 6.25 to find out the gallonage.

As an example of this take a circular pond of 12'-0" diameter x 4'-0" deep so:

6'-0"x 6'-0"=36

36x4 x3.142= 452.45 cubic feet.

452.45 x 6.25= 2,827.81 gallons.

There may well be another method but this is acurate and needs to be so if one ever needs to calculate medication for fish.

David.

[canuckamuck]

I did not mean to contradict my initial suggestion. UV pump will definitely end green water. I was trying to imply that filtration alone will not remove green water.

Blanket weed is algae, other names for it are thread or string algae We use to call the cause of green water - liquid algae. However I expect terms are different for different regions.

I agree with your suggestions. And your pond sounds like what I would build if I had a decorative pond. Currently I have several 6000 liter tanks plus a pond but they are for commercial fish.