opening my pool after algae

Hi,

So summer 2015 bought a Coleman above ground 16ft by 48". We live in Southern Louisiana.. tons of rain... tons.. for days.. electricity went off and so did the pump and we didn't realize it till much too late.. severe algae problem. Could never clear it up. Drained it and left it uncovered all winter. So for the last month we've been working on it on and off.. Got a sump pump, drained it, bailed water and brown/green algae for hours... then scrubbed down sides and bottom. Ok.. today its' almost new looking. I'm refilling it. What do I do to keep the algae away.. cause no doubt there are spores somewhere.. and how do I reopen my pool? I don't want to go through this again. Please help!