Closed loop through corner overflow

I'm pretty determined to setup a cls in my new tank.

I would be hiding the pipes below the sand and inside the overflow so there are no piping showing besides the loc-line and intake strainer.

Here's a quick sketch. There are two outflows that would be connected to some type of wavemaking setup (scwd, chase controller) and would branch off to a few outlets.

Has anyone tried drilling (and sealing, I'd be using RTV 103) through the corner overflow?

 

... nevermind.

I started a comparison chart in Excel of the kWh cost to run different pumps annually.

I didn't realize how low wattage Tunze / Koralia type ph's are. I'll put up with the PH's in the tank and save several hundo's a year in electric bills (like $300-$400).