Anyone have experience with these? Have had mine running for 4 months now and it does not appear to have any impact on my Nitrates. Have been "feeding" (filter only) with vodka 2x weekly and adjusting effluent drip rate about every other day. Have removed all bio media from FX4- all other tank parameters are fine. Effluent Nitrate is at 0 but tank Nitrates are still a challenge and require 1-2 large water changes a week to keep at 20. 14 Mbuna in 65G tank. Any thoughts or suggestions would be appreciated.