well the calc says if i do 3 75% water changes it should bring the nitrate down to 15ppm so ill do thatCould be a lot of die off maybe from the live rock going into a sterile water? Idk seems a little weird… I have around 100 right now and my corals are fine and loving it! I can’t get them down with chaeto or carbon dosing… water changes don’t budge them either.. my system was purchased second hand and is 10 years old but was a fowlr so it was heavily fed and never really maintained for corals.. I think the rocks bound it up pretty good since the sand bed is only 1/2” deep at best.