>>7430286 (lb)

using hydrochloric acid to balance pool or spa pH is not a one time thing.

as the water gets aerated from splashing, or running spa jets, or water is added, or chlorine (frequently in the form of 12% bleach) is added, or sodium bicarbonate is added to maintain total alkalinity, or calcium chloride is added to maintain calcium hardness, acid must be added to maintain pH between 7.2 and 7.8 (legal limits) with a target pH range of 7.4 - 7.6. (see also: Langelier Saturation Index)

any adjustment to any part of pool water balance chemistry will necessarily change other components, requiring addition of other chems.

yes, they may have been up to shenanigans, but they may also have switched to a different pH balancing method such as sodium bisulfite (dry acid) which is safer to handle and easier to work with.

yes, they could have been dissolving bodies, but that's a very sloppy way to dispose of evidence.

I rate unlikely/10

t. certified pool operator

>>7430754

good question. and the answer is; it depends.

how busy is the pool?

a place I worked at in a resort town has a 15,000 gallon pool. busier in summer, quiet in spring and fall, busy-ish during ski season.

not unusual to go through a fifteen gallon barrel of acid in a month.

extrapolate: pool double that size, probably more use year round, plus "poolside events" 100 gallons might be a six month supply.

also, children in the water require more sanitizer than adults in the water. more chlorine pumped in means more hydrochloric pumped in.

(btw, for anyone reading, stay the fuck out of any public swimming pools. nasty af. I keep mine squeaky clean, and I hate to even reach in for a sample to test)

>>7430899

exactly so.

downside to this is that more acid lowers total alkalinity, so you add bicarb, which raises the pH, so you add more acid.

(also: a. chlorine is more effective as a sanitizer at lower pH and b. outdoor/rooftop pools require a stabilizer because UV breaks down chlorine, but the stabilizer will also inhibit the chlorine sanitizer from working.)