I use one of those algea scrubbers that looks like a scrub brush you use to clean tires, but with a nylon pad instead of bristles. Can't remember the brand name but I got it at Petsmart for like 6 or 7 bucks. Cheap and works like a dream :thumb: . The only downside to it is you have to get your arm in the tank to use it , but for as well as it works who cares. Other than that a nylon pot scrubber will work good .