I'm doing a pretty similar setup right now and my plan is to use a one way check valve mounted on the pump inlet. This setup will still require priming which can easily be done by opening the pump housing and pouring a little water in. In my case, i'll be mounting the aerator head low on the tank so i'll also be able to partially fill the tank and it will self prime. I got some inspiration from here:
http://www.bigwatersedge.com/bwevb/s...+bucket&page=2