wonderful thing to wakeup to... air pump turned water pump

[Gazingatstars12]

So last night I did a nice big cleaning in my community tank. I hook everything back up and goto bed. I wake up this morning and the community tank is overflowing and my mini puffer tank right next to it is half empty. Water must have gotten into the air line and when I turned the air pump back on it started pumping water from one tank into the other. Anyone know of any way to avoid this from happening again? I'm guessing valves in each air line before whatever I have hooked up?

I had them right before the outlet on the pump but obviously this didn't cut it

[dmolavi]

Check valves in the airline. They're about $2-3 at your LFS.
Air Pump Accessories: Air Check Valve by Tom Oscar Aquarium Products

[Gazingatstars12]

I had check valves coming out of the air pump. But after that one line split going to the other tank which is what caused the problem. I'm assuming I should out one on each line going to each air stone /ornament?

[dmolavi]

That's correct.

(Edit: deleted link to gang valve, it didn't include check valves in the lines...oops).