This site has been a lifesaver. We are a first time pool family this summer because our neighborhood pool closed. We have a 15 foot by 4 foot pool vinyl above ground pool, with a separate SWG. I was naive and thought the SWG monitored the chlorine amount. Well after about a month my pool started getting cloudy, and I tested and found I had zero chlorine! I've been adding bleach, per the site recomm's , and it temporarily raises the level to acceptable but then disappears again. I've deduced that I must not have enough CYA. I ordered the testing kit you recommended here and it's on it's way. Meanwhile I went to the pool store and got some cya and put about 1.5 pounds in a sock and hung it by my return as recommended. Unfortunately I don't have a way to measure my cya until the kit comes. Was this a good idea considering I don't actually know my cya level? The pool store guy said if I haven't added any cya at all then my level is zero, so I figured it was safe to go ahead and start. Do you agree? By the way we have 7 kids, so the pool gets a lot of use, with at least 2-5 kids in it at any given time. thanks so much for your help!