Hi.
I've had this problem before to. When I started sw I had a huge break out of ick and brown diatom. (also know as the dreaded brown algae) I would clean and clean and clean with my mag float but it just kept coming back. I found a filter know as a diatom filter. Which obviously kills diatom algae. It also killed all of the ick and green algae! I bought one from ThatPetPlace.com for $130 with free shipping! It is an amazing filter hooks up just like a canister filter. It will kill all parasites, ick, diatom algae, allfreeflaoting algea, all algea on tank walls, (excluding coralline algae) and the best part it will harm nothing in your tank. Great for fresh and salt water! Very good for new cycleing aquariums (which mine is) or well established aquariums. I highly recemend!