hello i have a 55 gallon tank that i have set up for sw fish only. I set it up june 24 and had it going for about two weeks levels were good so i added a few damsels (3). Abount another week to week and a half went by and i started noticing brown alge like stuff on glass and sand so i did about a 40% water change and cleaned it up and everything went crazy. Store owner told me the water change set me back and i should have changed water during the cycling period (is this true). Also its now about almost two months and the temp is 80, ph, salinity are fine, the amm is less then .25 but not quite zero. nitrate is about 20 to 40 ppm. But my nitrite is off the chart. ive been adding prime or niteout but doesnt seem to help. Should i be adding it everyday and shoould i do a water change. The brown stuff appeared again yesterday but im leaving it alone this time. i use an API sw test kit i have a marineland c-360 canister filter as well as a 70 gallon basic over the side filter. ANy help would be appreciated as i am starting to get frustrated knowing it takes time but not seeing any change in the nitrite is making me wonder whats going on.