i know deep sand beds are often used in marine setups for filtration. Could those same principles be applied in a freshwater sump with a deep gravel bed. I often see people post that gravel over a certain depth will contain anoxic pockets and this would be bad if a fish were to be exposed to it. But could it be done in a sump where a fish doesn't have access. And if so wouldn't the anoxic areas "feed on nitrates." I have no idea if it would work or not but it would be nice if did. Would give me a reason to get that nice 125 gal reaf ready tank I've been eyeballin'
Just wanted to know if anyone has tried something like this or if my reasoning is completely off, wouldn't be the first time,LOL