Mine stay between 0 and 5 also. Using a fuge with miracle mud,small amount of sand, LR, & mangroves. Now for the kicker.... I turn my skimmer about 3-5 days a month!! Oh yeah, include the 1.5 lbs per gallon in the 155g tank, 3 1/2" sand base, 2 medium tangs, 5 b/g chromis, 1 carpenter wrasse, 2 shrimp gobies, pair of large clowns, 1 b/w chromis (yeah, right. he acts more like a damsel), midas blenny, forktail blenny - maybe I got a small bioload???
Anyway, zero is not mythical.