What to do with old MA?

[PoolDoc]

Just added a "muriatic acid" section to that page:

Muriatic acid
(AKA MA, hydrochloric acid.)
MA is something of a challenge to dispose of -- you can NOT simply pour it out, put it in the garbage, or pour it down the drain. If you can't use it, there are 3 options I can think of: give it away, neutralize it, or dilute it.

Giving it away so someone else can use it, is your best option. Another pool owner may need it, or you could give it to a brick mason or concrete finisher. You can also dilute it, and then dispose of it over time. If you dilute it 5:1 (31% down to 5%), you can safely flush 2 - 4 cups of the 5% acid, each time you flush. Or, you can neutralize it using borax 2:1 -- eg, 2 cups of borax for 1 cup of muriatic. Do NOT try to neutralize it with baking soda or soda ash; it will FOAM furiously, and spread acid everywhere! Once it's neutralized, you can flush it over time (NOT all at once) OR use the resulting boric acid mixture as a mild herbicide or wood preservative. (Adding a bit of detergent, and then spraying it on unpainted wood surfaces inhibits fungal growth and rot, and if it penetrates, inhibits termites.)

[JimK]

Thanks Ben.

I also wonder how much strength it has lost sitting outside in the plastic garbage can for two years?

[PoolDoc]

None.