I am currently using a single K8 but the magnet is not strong enough to hold where I need it through 1" acrylic, so what are my other options for powerheads, ruling out closed loop. I don't want to spend the money for MP60's, which would be ideal, but I just can't fathom the $750 for one of them. What other options do I have. My work has been crazy for the last year so I am sort of out of tune with what is currently available. If I could find some way to make the magnets stronger on the K8's I woudl just buy a few more of them.