Several years ago I discovered the joy of flocculent and vacuum to discharge. Yes, outdoor pool.

The local pool store charges $20 for a four pound tub, $5 a pound for a very, very common chemical used by the ton in water treatment plants.

The chemical is aluminum sulfate, aka alum.

You can buy this for +/- $1 a pound from taxidermy suppliers! I bought my first at a supply house in Broomfield, Colorado when I was on a road trip out west. Free shipping! My latest acquisition is from Jim Allred Taxidermy supply:

http://www.jimallred.com/SearchResul...?KeyWords=alum

I bought 25 pounds that even with shipping cost me only about $43, $1.72/lb.

Not exactly pool supplies at your grocery store, but not a bad money saver.

Alum also ties up phosphorous, an essential nutrient for algae. So, in theory, use of alum may also reduce algae.