Strong Magnets for Thick glass

[GoToSleep]

Looking at the new Tunze stream pumps, I see that their magnets are rated for glass up to 25mm (0.98" thick). Do any of you have experience using these on 1" thick glass? I'd hate to make such a sizable investment only to have my powerheads dropping off of the glass or sliding around in the tank.

 

[hwttdz]

If it's rated to 25 mm you should be set with 1 inch glass. Their measurements probably both leave a safety margin and aren't that precise (to distinguish between 25.4mm=1in and 25mm).