Alight I have been thinking about my Nitrate problem, and the fact I have not been able to bring them down much despite my efforts. This afternoon it occurred to me, I may be short-circuiting my sump. I have my return pump turned up to almost max. I'm now thinking I should turn it way down, and give that water more time sitting in the sump. Since there is no live stock in the tank there is no point in having it set so high. What are your thoughts?