DIY Nitrate Filter

AbbeysDad

Correction - after a day or so I noticed a bulge in the top of the sand canister. Apparently trapped air and/or gases. When I unhooked the hoses there was a large rush of 'air'.
I reversed the flow through the sand so the Tom pump is pulling from the top of the canister. I realize now that this is the only way for this to work properly without some kind of venting (which could cause leaking).

beetlebz

Id personally like to see the filters separated once they have both had a chance to mature for a month or two so the nitrates in and out could be tested independently. My 110g is almost completely covered now with Water Sprite and so far the nitrates are still 'blood red'. Stupid tap water. I need to recheck my 20 long planted, ive opted for 2 small water changes a week instead of 1 big one every week or every other week to see if that would help too, ill test it tonight to see what comes up. So far, just plants to remove nitrates has been a bust

skelator

i havent noticed any difference in plants helping yet either. if there is a difference its almost nothing as of now.

AbbeysDad

Well the sand filter canister was a bust as the flow rate through it slowed to nearly nothing. I suspect that with time and the slow (3.5gph) pump flow rate, the dense sand packed and if not plugged, severely restricted the flow. I tried a smaller canister with <= half the amount of sand, but after a couple of hours the flow reduced to drops again.
In thinking of what else might work, sponge came to mind, but I don't have enough on hand for that. Pot scrubbers, gravel?
Instead, I filled the canister with polyester fiber floss which should provide a satisfactory platform for beneficial bacteria and serve to polish the water before returning to the tank.
With all of the swapping, one of the siliconed "T" 's in the original canister came loose, so I redid both fittings with the glue gun.

Attached Images

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skelator

thats why i didnt use sand, that was my fear aswell. i just went with regular gravel as i had alot of it onhand. i dont know if i wasted my time and money as of yet its still very new. i figure worst case i can do dump some floss in there like you did.

AbbeysDad

Sand seemed like a good second stage. Not so sure the filter floss won't also restrict flow when it begins to load with 'stuff'. I may need something else like more open cell foam???

Gravel could work, but I think the flow rate would need to be very slow I think. The point of the Matrix and De*Nitrate is the macro/miro pores that may encourage anaerobic bacteria with faster (than trickle) flow rates.

skelator

i would have liked to use bio balls but i didnt have any and i was impatient. i read alot on the subject and from what ive read theres no reason the gravel shouldnt work but that remains to be seen.

AbbeysDad

Although bio balls are good for aerobic bacteria in a wet/dry sump to handle ammonia and nitrites, I don't think they'd be a good choice in a denitrator. You're better off with gravel or some other material that serves as a platform as there is much more surface area.
(The Aquapure for example uses open cell foam - 4 tiers, coarse to very fine).
Still, with gravel, I think you'll need a trickle flow through there the get the oxygen level low enough to support anaerobic bacteria.

skelator

too bad i couldnt get my hands on that foam thay use. i also wouldnt mine feeding the coil if i coukd figure a way to do it without getting air into the system.

AbbeysDad

You indicated you were using gravel - where does "feeding the coil" fit in?