Dougs Reef

[HaZRaTTy]

You plan on building an overflow box right?

Anyways if I was you I would, and just run both drains as drains and run a herbie system. I have no clue why people run bean animals I don't understand the concept over a herbie system. I have a durso right now and its a PITA.

I guess if you were to go with 3 holes in your overflow and drill another I would add the 3rd as a return. I would drill the 3rd hole to be bigger then the other 2 and use the bigger of the 3 as the emergency drain.