I like the shop vac thing, pretty cool. With my 20 gallon quarantine, that sits on the floor, I use a powerhead. I attach one piece of tubing to one end to siphon the debris and another piece of tubing attached to the powerhead goes into a bucket to siphon the water for water changes, works great for me. With my 90 gallon display I just do a straight siphon into a bucket.