What Marty said. Full speed is a killer for your electric bill, too. According to Pentair, a 3450rpm pump running at 1/2 speed uses 1/8 as much power. Mine at 3450 draws 2530 watts; at 1300 it uses 111 watts. I run mine 9am to 8pm at 1650 (260w; 25gpm); then 1am to 5am just for the skimming at 1600rpm. As people here will quickly point out, it's the chemistry not the pump and filter that keep the water sanitary and algae free.
BTW, that little ball on the ozone generator, you set between the two lines at full pump speed and then leave it regardless of lower speeds. If it's really stuck at the top, just flick it with your finger and it should come loose.