Lucky to have a handy exit point just behind the aquarium. Used 1/2 " PVC thru the floor, tubing to the exit point. A small piece of foam, no more than 1" deep (more will restrict air draw) to muffle air intake on outside. Cover outside end with plastic screen, secure with foil tape and/or cable tie around pipe. Made a big difference in tank ph.what does everyone use? pvc pipes or tubing?