Welcome to RF =)
I just upgraded from my 20 last month and have started my first experiment with a sump. I have read before that new pvc parts can actually cause some micro bubbles until they build up a for lack of a better way to say it slime coat.
I'm thinking there is some truth to that because i am about a month in on the new tank and my micro bubble problem is gone and i have actually as of last weekend removed all of the pre-filters from my system (overflow box, skimmer, and return pump).
I don't know if that helps you out at all, i suppose you can tinker around with it if you want, or just wait and see.
Any other questions feel free to ask, everyone on here is great and has been incredibly helpful guiding me through my first marine tank.