Magnet cleaners...

[vetteguy53081]

Tunze strong and strong plus one of the best

 

[Idech]

The small mag float has scratched the glass of my tank but I never had a problem with the big mag float (I had one for a very long time and just bought a new one to replace it).

With the small one, the space between the » teeth » of the cleaner are small enough that the sand gets caught in it and scratches the glass. On the big one, the sand doesn’t get caught.