Supposedly, LR that is porous will have anoxic regions in it... Thus we should get nitrate removal.
For what it is worth I don't think a 9 inch sand bed will do any good. Stick with 4 inch, it has been proven to be the best depth for a De Nitrifying sand bed. I keep about an inch to an inch and a half in my 90 and 4 inches in my 40 gallon refugium. I have about 60 Lbs of LR in my tank and about 20 Lbs in my refugium. I do 10 gallon/week water changes and I have no nitrates.... is it the DSB or the water changes??? I don't really care, I'm just happy that I don't have problem algae, and I do have healthy corals and inverts.. (or so they appear healthy).
|