Ok guys here is my dileman.... I have been having a green hair algea outbreak. I have tried evertying from full black out for 10 days to API algea chemicals, to no avail its still here.. So i started snooping. I tested my RO/DI water straight from my reserve tank in the basement and its giving me an Nitrate reading of 10ppm. This is weird any suggestions. The RO/DI system is only 4 months old. I ran it for 12 hours prior to use and with my TDS meter it reads 00ppm... You guys think this is why i am having algea problems? and what should i do about this Nitrate reading? I think there is something in the basement that is getting in the RO water to cause this because all other readings are 0. I used 2 different test kits with the same result.