Dumb Question About Powerheads

The algae on my powerheads grows faster than anything on the planet. I clean them off every time I do a water change (once a week) but they sprout almost overnight. I clean them off. The algae grows back. I clean inside them with a Qtip.......under the blades.....

Is there a dip I can soak those babies in that will kill the algae?

My phosphates are 0. Water parameters are excellent all across the board. Having some trouble keeping the pH up to 8, and the kH up to 8-9, but I stay on it every day.

Thanks!