Here is a one to test you

Im helping one of the lads at work build some a new filter system for the large pond. We are using two 800litre IBC's. Each one has a compartment inside. One of the compartments is about 300litres in volume. We want to fill it with open cell foam to take out debris from the water. We have been told we cant use normal foam, it has to be aquarium grade.

Q1 - is this true? Will we kill the fish by using standard foam?
Q2 - where can we buy open cell foam from to do the job? We are hopefully after some coarse open cell and something a bit finer. Probs about 2 sq metres of each.


Thanks in advance,
Darren.

The previous system worked well and was 4 off 200litre containers. No'1 was empty, sludge settled in bottom. No/.2 had foam inside, water rose from bottom of it (through filters). No. 3 had loads of pieces of cut pipe (biological filter). No. 4 was empty and contained the return to the waterfall. We are basically replicating this but bigger, plus the IBC's have taps in the bottom so they can be drained one at a time every few months to wash them out whilst maintaining the bacteria levels.

my dad has kept koi for years, he used three filter chambers, each about 1000 litres, one had aquatic foam in and two had massive filter brushes (much easier to clean) along with various UV filters and airpumps too.

I can't definativly answer your question, but based on the experiences my dad had trying to use cheap stuff every now and again, I have to say - DON'T. Fish can be very sensitive, especially koi, and at best part of £1000 per fish - not cheap to get wrong!

If its just a normal pond then its worth experimenting, or if its filled with golden orf, because they are double hard.

Link
Funnily enough, it's very similar to some of the stuff I've used for my air filter!
You should definitely keep some form of settlement at the front end to reduce the loading and required maintenance on the foam filters. The dimensions / volume of the first chamber should be dictated by the flow rate through the system to give sufficient residence time to allow settlement. You need to flow horizontally through this section and a wider/longer shallow section will allow better settlement.
I have to say that I know nothing about keeping fish but I do treat contaminated water every day.

[Edited on 1/6/09 by Richard Quinn]

[Edited on 1/6/09 by Richard Quinn]

Fantastic link Richard. many thanks. Looks exactly for the job.