Any way to block the sun light from the tank? Maybe cut-to-size card board or 1/8th inch thick wood.
When I moved my tank away from the sun I have not had a speck of algae. Ever. I feed my fish generously and have moker filtration.
An AquaClear 110 moves 500 gallons an hour. I have one on my 40 and two on my 100. Because of the way I have the inlets plumbed I'm getting a true eight water turnovers per hour in the 40 and ten turnovers in the 100, I believe. I consider that the minimum required. 25% weekly water changes too (using PRIME or Stresscoat).