Having found that one of the local pool store's 12.5% chlorine is a better deal than the available bleach, and not wanting to handle quite so many jugs, I've decided to start using the former. But this has produced a problem.
The jugs in question are 5-gallon returnable, blue plastic. There are two caps on the top. One is a bit smaller than a dime, the other roughly 3" diameter. (I can post a picture later if needed.) It looks to me like the small cap is supposed to be an air vent while the big one is what I should pour out of. But said big cap is so tight that it won't budge even a fraction, no matter how hard I try or what tools I use.
That made me suspect that perhaps the big cap is for filling and I should be pouring from the small one, but it's too small to manage a simultaneous flow of liquid out and air in. The result is that the flow is too uneven to corral it into a reasonably-sized container for measurement, and I have to either spill a lot (very bad for very obvious reasons) or pour it straight into the pool (impossible to control dosage adequately). Currently I'm doing the latter and erring on the side of putting more than necessary in, but I'd rather have proper control.
Obviously I could ask at the store, but I don't trust them even that far.
Is anyone familiar with these containers? What am I missing? Thanks for any insight.