My favorite water mover! I use several SLWs (-10, -20, -30) and they all work very well. Two are in a caustic high solids environment, and they keep on doing what they do. Simple, inexpensive, and reliable. These will move water and will do so quietly. Regarding the magnet, with proper installation, it will hold well on glass up to 10mm. Attach the pump to the inner magnet and hold the pump to the glass with the outer magnet (three piece mount). This review is not fake nor sponsored. Check out my Instagram at @telegraham.
I never had a magnet as week as this one is. It does not hold at all. Perhaps it would work on glass 1/8 in. or less. My tank is 1/4 in. This pump is useless to me.