Folks, if you've recently upgraded or renewed your annual club membership but it's still not active, please reach out to the BOD or a moderator. The PayPal system has a slight bug which it doesn't allow it to activate the account on it's own.
Agree with Paul and Amado. I would get a sump bigger than 20g. My tank is 80g and sump is 30g/40g. One other thing I do to prevent back flow is I keep the return nozzle a teeny bit up above the surface.