Plumbing Triple Tank Set-up

[Richer]

Personally, I wouldn't have overflows on all of the tanks, only on one of them. I would put the return line on one tank, then the overflow on the tank farthest away from the return tank, then just plumb all of the tanks together (either by U-tubes that extend far enough down the tanks to prevent siphon breaks, or by drilling and connecting them). That way, you'll essentially have one big tank. Additional flow can be done with powerheads of closed loops.

-Richer