Welcome to AA!
I've never had a need for a UV
sterilizer, so I'm no help there.
I'd definitely up the pump capacity. Your current setup turns the tank over about 5.5 times per hour. Six to ten turnovers per hour is the range you want to shoot for, possibly more in a marine aquarium.
Just some FYI: Spell check is your friend. Questions are much easier to answer when they're written in good English. No offense intended, especially if English isn't your first language.