US distributor for power magnets?

[Pyrrhus]

i work for an LFS in arizona and was wondering if you could give me some info on a US distributor for the power magnets for cleaning aquariums. we have found them as the single most useful tool in our service company and need to get the largest model available. the magnet needs to be able to work with up to 2" acrylic tanks. thanks in advance...pyrrhus