Hello!!! This is my first time plumbing an overflow/sump. It is a predrilled tank with 2 holes at the bottom of the overflow. I’m attempting to run it as safe as possible (preventing overflows), but there is no room to drill a 3rd hole. Previous owner ran the tank with one drain and one return. Is there any other way to run the tank safer in the event of a drain clog or lose of power.