i want to move debris off my 120 gal glass bottom. which of these do you suggest? in the past i would point power heads at the bottom and the movement would be less than i would have thought. also was wondering about too much current for a healthy environment for bowfin. finally if i buy a larger one could i use my dimmer to adjust the flow? http://www.fosterandsmithaquatics.com/product/prod_display.cfm?c=3578+4586+15955&pcatid=15955
