A couple weeks ago I changed our spa water, and used the muriatic acid to lower the alkalinity in our tap water, which is very high (400+).
I am quite pleased with the results. I added the acid gradually over the span of about a week, give or take.
To be safe, instead of just pouring the acid directly into the spa water, I used a clean ice cream bucket to scoop up about 3 quarts of water out of the spa, then added a few ounces of acid, mixed it into that water, then gradually added it back to the spa.
I used maybe 12 ounces total, vs the 24+ ounces of Ph decreaser it used to take. Cost of a gallon of this stuff was around $2 for a gallon. At this rate, I'll get a couple years out of that gallon.
So far so good.
