just run two tubs facing each other and use a shared res imo. you might have to diy a little on mounting the light to get the right footprint, but I don't think you should try and attach the tubs together and waterproof them over running extra tubing to/from your res.
You are absolutley right, IDK what I was thinking
Using those simple pass throughs made for cvpc electrical conduit is much easier, cheaper and a whole lot less problematic than installing 1 and3/4in. Uniseals@ on a 45 degrees angle.
God Bless the Internet, IC and people like you, HeD33!
Thanks!