DIY Coil Denitrator Plans

[rsman]

The BioBall limited surface area might be the limiting factor for your DIY denitrator here.
as long as the coil length is chosen correctly (in a correct ratio of diameter to length) its really not, the amount of surface area required is soo small that the pipe holding the bio-balls alone is close to enough

With either substrate you should be able to increase the flow rate too.
many ppl ive replied to should increase the flow rate and make no other changes, most dont push there denitrators to anywhere near there limits, then complain that they dont work well enough.

The original Seachem recommeded flow rate for Denitrate is <50g/h.
im not gona go hunting but if i recall correctly that flow rate is for that media in an open flow, not in a denitrator, with that flow rate you are hoping to process nitrate passively like live rock does, a functioning coil denitrator will remove all of the nitrate that goes into the unit. instead of some of it.

And if the coiled tube didn't consume all O2 with higher flow, the bottom layer substrate will.
unfortunately when this happens the entire chamber is effected, while some higher density media might still passively remove nitrate the chamber itself wont and you will have nitrate in your water

another minor issue to consider when experimenting is that if you have too much surface area for the flow rate of the coil you will create hydrogen sulfate gas, a bad thing.