Hi there !Do you have a planted tank, or just a 'fish tank' with plecos and snails? If you just have a fish tank, then just overfeed a little bit, and throw in a bit of organic matter to decompose. That will create a little bit of ammonia and algae will surely follow.
If you have a planted tank, I wouldn't recommend doing any such thing. It would behoove you to just buy algae wafers to feed the plecos or boil a little spinach etc. Asking to grow algae in a planted tank in a controlled fashion...I wouldn't recommend that.