Sorry to whomever posted this advice. Poly will prevent the algae, not clear it out.

You need to measure both Combined Cloramines (CC) and Free Clorine (FC). Added together they equal your Total Clorine (TC). When your CC comes down to less than .5 you've eradicated the algae. Stick with just clorine (Chlorox, or the 12.5% you can get at many pool stores) and avoid the other branded "shocking" treatments.

You also need to run your filter 24/7 during this time.
And vacuuming to waste is simply diverting the water sucked up by the vacuum out from the pool system (on to the lawn, or whatever) to save stress on your filter. Some filter systems (like my Hayward EC65) don't have this option.