I'm running a "Berlin Method" 50 gal. reef tank. Started tank end of November with 60 lbs. Nature's Ocean LS. 1st week of Dec. added 70 lbs. of LR. 4 powerheads on a wavemaker for movement and a Berlin HOB. Started fish around new years. Now have 7 small fish, 3 cleaner shrimp and a couple of pieces of soft corals. All are doing fine NH3/NH4+ @ 0, but can never get NO2 lower than .15ppm after 20-25% h2o change. Do I need to invest in canister filter. If so, which is best/quietest? Or am I totally missing something? Do "Berlin Method" tanks ever get down to 0 nutrients?