Went to buy some MA today and they were out at the hardware. Right next to it was Sulfuric Acid for about 20% more in cost and 1/4 the size. I was unable to find the concentration on the bottle. Is it safe to use Sulfuric Acid to lower PH in a pool? Anyone have an idea how much one quart might lower PH in a known pool size versus MA? I realize the strength of what I found is left out...