I agree, I live in SC and we have temps in the 90's consistently--I see the sun beating down on your black sump outside in Florida--Even in the shade thats got to be to much heat.
In addition to removing the lids/top of the tank I would also place 1-2 fans under underneath circulating cooler air up and around the tanks, after all water is nothing more then a giant heat sink.
As for your return pump you need a pump that is rated for 11ft (would not hurt to build a stand and elevate your filter altogether--looks like you could shave 18 inches off your return, and save electricity) I like harbor freight I buy cheap tools-- the illegal aliens borrow them from the job site I go back to harbor freight I buy cheap tools and the circle is complete. I like harbor freight they sell cheap knock offs that work (for the most part) but I dont believe that they are your best resource for your return pump.
A good pump is money well spent.