Hello, TFP peeps! Long time lurker here with a question regarding chlorine math!

I did try to find the answer by continuing to lurk but the particulars are very specific and I struggled with search terms which would successfully extract this content from every other post on the forum.

So:

Let's arbitrarily take a 20,000 gal pool. Measuring in "parts per million," we get:

20,000 / 1,000,000 = 0.2 gal = 25.6 oz = 1 ppm.

So "1 ppm" of "anything" in this pool is 0.2 gal (25.6 oz) of that substance.

Logic would then suggest, to raise the chlorine content of this hypothetical pool from "" ppm to "x" ppm, I need 25.6 oz of chlorine. The pool calculator sort of agrees, but that's where the subject line confuses me - 6% vs. 12% vs. 100% chlorine. Unless... when we sayx+1"+1 ppm of chlorine" we actually mean "+1 ppm of [12%] chlorine(plus 1 ppm of 88% more water... )"?

Pool calculator says:

To go fromtoXppm FC, add 41 oz of 6% "bleach" or 21 oz of 12%.X+1

(somewhere around 9.7% bleach will give me the 25.6 oz mathematical target)

So I guess that's my question - when we say "ppm chlorine" in relation to FC, it would seem we actually mean "ppm [~12%] chlorine"?

True / False?

Thanks!