Cheryl's 165 Gallon upgrade

[Madmak]

I understand better now that I had a closer look at the pics. That's a difficult layout to make work.

You could definitely plumb the 2 existing holes to an overflow at the back of the tank. The wider it is the better the surface skimming. Hiding the plumbing with rock would be fairly easy as well.

2 separate overflows gets tricky to tune and you really don't end up with an emergency drain.

Post a few more pics and you'll find a solution.