I'll look into it - but we havent had an algea problem at all and we have the clorine floater on the lowest level. Perhaps it is because I am in Phoeniz, AZ where it doesnt rain ever. The wife tests the levels every few weeks and all is well. We also took a sample of water to Leslie's last week while shoping for a cover and it came up "good". Perhaps we need to get a better testing kit as ours just does PH and Chlorine levels...thanks for the info!