What if i use a small air pump for large tank?
If it pumps air all the way to the bottom of the 85g tank, it is a great air pump. You do not need to get a new pump. You might want to get a rebuild kit for it, though. It will be working hard and the little rubber gaskets inside will wear out sooner than pumps on shallow tanks. They are cheap, $3 or so. Easy to repair, just need a small screwdriver. Many of the smaller pumps are not strong enough to push air all the way to the bottom of the deeper tanks. But I use the Tetra Tec “Deepwater” air pump when I want to push air down more than 12″ in a tank that is not serviced by my linear pump. My Whitewater Linear air pump has no problems getting air to 17 tanks with “air to spare.” I bought a larger one that will be put into service soon. It should handle all 23 of my tanks and any more that I set up, up to about 45-50 outlets.
