Well, I called my mother, and she said it was indeed sulfuric acid that we needed for the cement, but just to be sure, I looked up 'pool acid' online.
"IDENTIFICATION OF PRODUCT
Product Name: POOL ACID
Common Chemical Names: 40% Sulfuric Acid Solution, Pool Acid
Chemical Names of Ingredients: Sulfuric Acid, Water
Chemical Family: Inorganic Acid Compound
CAS Registry Number: 7681-52-9
Empirical Formula: H2SO4
Molecular Weight: 98.0"
I got that from a 'material safety data sheet' pdf posted on a pool products manafacturers website.
But I'm glad I checked.