I have a 30 gal garbage can that i use to do this but the reason why mine works is that the big reef tank is on the first floor and the garbage can i use is on the second floor so mine works through gravity, but anywways ill tell you how i did mine, so i installed a bulkhead into the side about 2 inches from the bottom of the can a one inch bulkhead and attached a ball valve directly to the bulkhead then attached a hose adapter to the ball valve and then attached the hose to the adapter then i run the hose down stairs to the tank now the key is to install another inline ballvalve (they sell these) at the end of the hose (for control) and then you can just simply close the ball valve at the end of the hose and open the one on the bulkhead and the there ya go, but i recommend attaching another smaller piece of hose onto the end of the inline valve so you can stick the hose into the overflowbox and then the water runs into your sump and mixes with the preexisting water alrdy in the sump. but if you dont have the ability to use gravity you could just as simply use a big powerhead and attach a hose to it with the ball valve and then there ya go all you would be doing is strainning the powerhead alil when you have the inline valve closed. I love this way of doing waterchanges i dont have turn off my pumps or anything its great just the level in the sump changes for the most part.Oha nd i forgot to mention i run a one inch hose from the top of my tank to the bathroom toilet about 12 feet away and thats where my waist water goes or i use it to change water in other tanks i have as the reef tank has cleaner water than any other of my tanks.
