what % of filtration does substrate contribute

[Bad Inferno]

I am looking at changing from a planted 180 litre tank up to a planted 390 litres tank.

On the basis of the same fish load, could I just move across my canister filter & UV. I really want to change my substrate to either sand or darker than it currently is. Thus my question, how much does the tank interior rocks and substrate really contribute to the filtration process. I would move all plants together with the filter.

cheers

rob

[Nathan]

hey rob, well im no expert but i know that there is a large volume of good bacteria living in your gravel which helps with the balance of the tank. however depending on the cannister filter and its capabilities i would probaly buy a bigger one. to work it out work out the volume of the tank and then look at how many litres per hour your filter does and it should do around 4 times as much as your tank is in an hour, so youl probaly have to upgrade filters.

HTH

[taksan]

Certainly 50% ... but because your cannisters cycled I wouldn't worry too much.