I tested my home water today(what I fill my tank with). Perameters: ph:7.6 Ammonia:0 Nitrate:0, Nitrite:40. So, a few questions. 1: is the water I'm filling my tank w/ contributing to my nitrate troubles. 2: how long will it take for the seachem matrix to start making a significant difference in my perameters. Last test on tank: ph:7.6 Ammonia:0.25 Nitrate:0 Nitrite:80. I have 3 turtles, oscar, 3 plecos in 240gal, and have been having nitrate troubles obviously. Took all the suggestions I got on here, & last week got another fx5, now running 2, some new media(seachem matrix), along w/ changing out my fluval zero-carb, carbon, biomax. Had first fluval for almost a yr I think. So, again, is my water source contributing to my troubles, is it still a good idea to water change often, and how long will it take for the seachem to make a difference. Thanks, hope to hear some answers soon