[untamed]

Originally Posted by martym

I was looking at my tank last night, and it dawned on me that if the aqualift were to quit or get plugged the main tank would quickly overflow. What do others do to have a safe guard so this doesn't happen? Other than having the tank drilled.

I ran a CPR overflow for many years. I don't think that what you've said is completely accurate. You should be able to shut off the aqualift pump and nothing should really change.

Now...if the aqualift remained off for days...things will eventually go bad...but nothing should happen immediately.

I didn't use an aqualift pump...I had the top of the overflow connected to the venturi of a powerhead. Even if the powerhead was off, or the venturi plugged...the system is still closed (vaccuum), so you shouldn't have an immediate failure of the siphon.