So I had a massive algae outbreak recently that required fish removal, breakdown and cleaning. So I used the opportunity to change out the substrate (the original was really not the right one). Anyhow all fish survived and are doing well (woo hoo!). So now I am thinking: if I put a small powerhead in, I can keep the water circulation up such that the algae spores dont have a chance to settle again. Has anyone done this in a freshwater tank? Obviously its needed in a salt tank.

Algae will come back regardless. You need to find the cause of the algae :)

*L*
How long do you leave the light on for? How strong are the lights over what sized tank?

What fish load? Cleaning crew? Yor cleaning regime? Near natural light sources?

Any info you can think of might help. Though a small amount of algae is ok an natural, when it takes over like you stated something isnt right

Is the tank planted that you need the lights on that long? I'd be shortening the light period and slitting it in 2 so that the lights are only running whle you are there to appreciate it :)

you need to identify the type of algae, then we can give you the preventive care