Thank you every one. You are too kind
first bits of plumbing. trying to keep it as simple and upgradeable as possible.
I can't afford a big pump right now but I'm making the drain big enough to handle the new pump once I have it
I dunno if the air intake will work or not (little ball valve in the pic)
I'm thinking no PVC glue on the drain since there's no pressure and salt creep should take care of a few small leaks.