I used half a bottle of concentrated bleach last year and my water starting sudzing up. I stopped real quick, discharged the water, and used a leaf net to get as much suds and toss it out of the pool. Scared me too much to try it again. I will try WalMart again. I was looking for 20 Mule Team and not thinking that it could be another brand name. Thanks. What kind of test kit do you recommend?