tank overflow prevention?

[Doug]

This is my take on this topic, so take it for what its worth.

1. I would never valve a drain.

2. I would never use a check valve.

3. Make the drains large enough to handle any volume or two drains or use an overflow drain as many have suggested.

4. Use a herbie, duraso or stockman overflow, to silence them.

Sumps & overflows are a very simple thing to not complicate and make them fool proof.