<a href=showthread.php?s=&postid=15167826#post15167826 target=_blank>Originally posted</a> by flrn
Has anyone thought of checking your source water? I had a HUGE GHA problem last year, and after 9 months of frustration and expense of testing my water, I finally broke down the tank and disposed of everything. Perhaps not the brightest of moves, but I thought it was at least a cure. Or so I thought. I bleached the tank, and purchased (at a great expense) all new live sand, rock, etc. And guess what.... the tank looks great, but is starting to grow the GHA again! can you believe this. Ok, so now I need to figure out why. I always knew it was either a nitrate or phospate problem. Bulbls replaced, so not that. Then I tested my R/O source water for nitrates with salifert. Guess what.. it was the same as my main tank (50) or 5 according to the low range. So I purchased new filters, and a TDS monitor which not alerts me to the detection of any nitrates, phosphates, and silica in my r/o water. I've picked the small bits of algae off of the plant in my tank, and am currently doing 20% water changes in my tank. Will keep you updated, but just food for thought to check the r/o system. You really want 0ppm reading, anthing else, and change the filters.