In the "pain department"?? I guess so, if you get it on a cut or in your eyes

Chem_Geek, if anyone is selling 15% muriatic acid, that is actually a GOOD deal for pool owners, even if it costs more. The vapor pressure of the HCl in 15% is low enough so that little off-gassing occurs.

This was actually one of my little secrets I hope to use to some day make money from commercial pools. That's not going to happen! So, here it is:

Regular 31 degree muriatic does MILLIONS of dollars of damage to commercial pools each year (trust me, that is NO exaggeration -- I can show you $2,000,000 in the Chattanooga area over the past 15 years), because of off gassing from containers of stored acid.

The solution?

Dilute it! 2 parts water to 1 part acid is ideal.

I discovered this by accident 25 years ago, and later discovered the reason.

If you use it all up right away, regular acid is fine. If you store it outdoors, it's still fine. But if you store it INDOORS, and can buy diluted acid, do it. You could dilute it yourself, but you'd need a full splash suit + gloves + face shield, and a place to work: it WILL splatter.

Ben / PoolDoc