what's causing the green water?

[AJ_77]

Originally Posted by Seriak

I believe, if memory serves, there was a post on this board a while ago about someone who had green tank for months and was about to give up when he checked and saw that he was using freshwater carbon. He changed it and everything cleared up almost immediately.

That was me. I unwittingly substituted the wrong carbon - same brand, but labelled "for freshwater use ONLY." Big duh! Apparently one of the additives that made it so marketable for FW was a ticking phosphate BOMB.

Even with totally green water, I registered elevated phosphate levels. After running the phosphate sponge, etc as mentioned above, it started to clear within days. The clams actually seemed to help too.

I can't get the thread up, as it's too old now. But there was a TON of advice and within a couple of weeks the tank was nice and clear.