Hi, great question!! Didnt know myself so did some research

FYI there is a 34.6% Hydrochloric acid in poolmath. I assume that would be pretty close to what you have

**Baume to percent**

The °Baume scale is an old antiquated method of measurement of a chemicalsSpecific Gravity. It was devised a long time ago and is a scaling on a hydrometerwhich measures the Specific Gravity of solutions.To really make things confusing there are 2 ways of using this scale, one for liquidsthat are more dense than water and one for liquids less dense than water.

Liquids with lower S.G. than water, S.G = 140 / (°Bé + 130 )

Liquids with higher S.G. than water S.G = 145 / (145 – °Bé )

So, if you have the °Baume of a known chemical, you could calculate the S.G. Fromthis you can compare the S.G. of the particular chemical and see what the actual %concentration would be.

**Example**

20° Bé Sodium Hydroxide NaOHSG = 145 / ( 145 – Bé ) = 145 / ( 145 – 20 ) = 145 / 125 = 1.16

If you look at the data of Sodium Hydroxide you will see that a S.G of 1.16 representsa concentration of approx. 15 %