I have a prism, happy with it, works good on a 55gal. Wish it had a taller tube as the flow is pinched 90% off to keep the bubbles from filling the cup with liquid. I can't quite make out how the surface cup upgrade works, I fixed mine. Put intake tube in a tube with a vertical slot and styrofoam collar. Works o.k. if you keep it clean. Even when it runs dry, the impeller stays wet, no harm done. if it does draw from the surface with no problems, I would go for it, my surface gets a bit of an oil slick without collecting from surface.
If you think doubling your efforts can compensate for lack of skill, there is no end to what you can't do.
