(See illustrations with air pump.) Hang gang valve on top edge of back of aquarium. Cut section of airline that is attached to sponge filter to nearest vertical valve spigot and attach.

Attach remaining airline to airstone and place airstone in back corner opposite sponge filter. Again, trim airline to length and attach to next vertical valve spigot.

Place air pump in cabinet or on floor behind the aquarium. Use the remaining airline to connect air pump to horizontal valve spigot, discarding any extra. Remaining vertical spigot should have no airline attached to it, so it can be used to "bleed" any excess air from the system, to relieve backpressure that would eventually damage air pump.

Cut airline approximately 6 inches from pump and insert check valve. (Check valves only allow air to flow in one direction - check by blowing into it.) On pumps with multiple outlets, each outlet should be protected by its own check valve.