Three observations:

1) In AZ, you'll lose a LOT of water to evaporation. I'd strongly suggest running the fountain with a dedicated pump on a time clock. Even here in TN, a fountain 'costs' a lot of water, but nothing it will in AZ. With a time clock, you can operate it only when someone is watching . . . and save water, electricity and pool chemistry problems.

2) In terms of water usage, cartridge filters use the least and sand filters use the most.

3) I believe the common pattern out your way is a 1spd pump with a time clock. If you are going to use an SWCG (salt water chlorine generator), you'd be better off with a 2 speed pump running on low most of the time. That way, your SWCG can run all the time, instead of just when the pump is on.

Ben