It has been crazy trying to get pool running, we needed bristles for pool head to clean, after returns for a few days, long boring story we finally got to START cleaning yesterday! Question? We vaqumed to waste until water level got down below skimmer, than I added chlorine. Our son in law who has somewhat more knowledge, plumber, understands pumps, etc., had a fit because I didn't get ALL the algae out! He said it would gum up the new sand in the filter. I know it is best to get out as much as you can, but I thought it was okay to let the chems start to do some work? He insists that I add more water and continue to vac to waste. Personally I understand, but...? Do you keep bringing the water levels up and vacuming to waste to get most of bottom debri out? Thanks!