On Tue, 24 Feb 2004 22:23:23 -0500, "Paulo" wrote:

Are you changing all the water once a month?

Even if he was, what does that have to do with alge?

He'll want to check his water supply for phosphates and see where
that stands. Next, post the tank water quality (nitrates, etc.) and
lastly, how long and how much light is there on the tank.