How much acid?

[Batgirl0916]

I was once told that I should not add more than a quart of muriatic acid to my pool in a day. Adding any more would be ineffective. However I have not seen or heard of this advice since. My question is then, how much acid should I add at a time to our 13,500gal pool? In my first testing of the season, my TA is currently 250 (My fill water tested at almost 500, so you can see my frustration.) I know to drop it to a pH of 7 or 7.2 and aerate back up. However, that is was off the scale high too (we have great water here). Suggestions on how much is too much?

 

[woodyp]

Add enough in multiple increments with retesting every 15 minutes and sneak up on it without bottoming it out. If it takes a gallon in a day, then that's what it takes....no issues there. If you're a solid no questions asked above and beyond 8.2, I'd add 20 ounces to start and see where it gets you...hopefully off the purple and into something you actually diagnose and then dose properly.

 

[Richard320]

My pool is not significantly larger than yours and I regularly add half a gallon at a time when I top off the water. I dribble it into the return flow in front of a couple different returns and I've never felt the slightest concern about it. It disperses fast inside the return stream. If you want an absolute rule, I think if you limited yourself to no more than a quart an hour with the pump running you would never ever have to worry about overdoing things.

 

[Batgirl0916]

What would you consider enough? 1 cup, 2 cups?

 

[Batgirl0916]

Great, thank you!

 

[Meadow]

What would you consider enough? 1 cup, 2 cups?

Use enough MA to bring your PH back down to the recommended level. According to PoolMath, a PH of 8 requires 38 oz or 1.2 qt of full strength (31.45%) MA to bring down your PH to 7.2.
Also, your test kit contains the acid demand reagent and literature, very helpful in determining the amount of MA required to bring down your PH. Did you try it yet?

I normally dilute 1.2 qt of full strength MA with water and broadcast around the pool twice a week.