Before I found this site, I followed that 1-3ppm no matter the CYA, I live in Mass. and in May/June the water was pristine crystal clear because the water temp was in the 60's/70's and then when the water started to warm up in July then the algae started. Water never turned green, just all over the liner, in the filter, even the clear view to see the backwash had green in it. I didn't understand what I was doing wrong. I was using gallon after gallon of Algaecide, still green. Then I found the chart on this site and 3 years later and have never had algae again. I use pucks to chlorinate in a floater, bleach to shock and have switched to Baking Soda and Borax.