Quote Originally Posted by Ohm_Boy View Post
I've seen some 3% off-brands around, and I think I recall seeing even less - like 2.something% in Kroger.

If they won't even print the concentration, I'd be real leery of it.
Your right, ohm; I'd forgotten about that 3% stuff.

Regardless, my main point remains: You have to see what the the stuff does in your pool anyway. Depending on how long the bleach has been sitting on the shelf at the store or in your laundry room it will almost always contain more or less active ingredient than is on the label; sometimes significantly more or less.

After a while you get an idea which stores move the stuff fast enough to always have "fresh" bleach available and which brands (or off-brands) give you what the label says it will. That will give you a good idea what a given bottle of bleach will do to your chlorine level but it will always be a bit of a crapshoot. Fortunately, even the limited accuracy/predictability we have is almost always good enough. For e.g., it doesn't really matter whether you have 3.2 ppm or 4.5 ppm so long as you keep it between the 3 and 5 (or whatever the best guess chart calls for in your case). If you dump in a bottle and only get half the chlorine you thought you would, dump in another bottle. No big deal. That's one of the reasons we test often.

We sometimes forget that the whole point of using Ben's Grocery Store Chemicals pool care method is to keep a clean, safe pool at a reasonable cost and with minimal hassle. Trying to test the chlorine strength of a bottle of bleach is distinctly not in the minimal hassle category to me (though it's an interesting academic exercise in and of itself).