Mtnman;
Close but...
Here in lies what I learned from a great number of years ago.
Once a Lead acid battery had been activated by adding the electrolyte to the dry cells; ONLY and ONLY distilled water should be added. Of course tap water is better than a dry Lead acid battery.:-)
There are specific gravity reasons. The reasons are varied depending on whom you are learning from or which book you are reading.
Adding electrolyte to an already activated battery will do it little to no good, and may actually do it harm, and while ph levels could help it will not make that much difference in a battery. It's the specific gravity that makes all the difference for lead acid batteries.
What comes out of a battery that is boiling over is actually several things. One of course being water, it is much lighter than the acid, and during even the extreme boiling of a battery such as a stuck in charge mode alternator the acid is 85% of the time left in the battery, so adding acid will change this chemistry of the liquid and the battery as a whole for the worse all the time it needs water. More importantly coming out of the battery is the hydrogen gas. This stuff is highly explosive, used we to touch this off on purpose as a plasma ball. Cool to watch and see, but really dangerous stuff and can at the very least leave you without eye brows for a short period of time.
Battery acid is actually fairly easy to purchase from a battery dealer, but they usually ask questions, such as if you have bad battery or if you just purchased a new battery. If you tell them you have a battery low they too will caution you against adding battery acid.
Not wanting to rain on your advice but water is needed, not acid.
Cheers!!
Bruce S