Newbie: How to calculate and reduce pH based on Taylor k2006 Acid demand test

[BullishBear]

Following are my current values (<facepalm>, I had my water balanced well until November start but last 2 months lost track):
FC: 0.5 ppm (going to use Liquid Chlorine or Bleach —> Please share the preferred option along with the brand name)
pH: >8.0 (the color is darker than 8.0)
Acid Demand Test: 1 drop of R005 resulted in between 7.7ish; 2 drops of R005 resulted in exact 7.4

Note: My TA is also low around 60ish and planning to use Baking soda (1 to 2 lbs) to raise which, per Poolmath shouldn't raise pH.

How much should I be adding Muratic acid to lower pH? The pool math suggests the quantity based on current pH value which is set to 8.0 as I don't know the actual value. Using the observed acid demand test (i.e. 2 drops to 7.4 pH), is possible to calculate the actual pH value? This way, I can use pool math to figure out the MA to use. Thanks much!

Side question: Please suggest whether I can add LC/Bleach, MA, Baking Soda (one after the other)?

 

[ajw22]

TA of 60 is fine. Do not add baking soda.

Tell PoolMath your pH is 8.0 and target is 7.6. Add that amount of MA. Test pH again after 30 minutes of water circulation. If pH still 8 or higher repeat until you get pH in the 7s.

Add chlorine and MA at least 15 minutes a part.

 

[jmastron]

The acid demand test comes with a chart mapping the # of drops and pool size to how much acid to add (either in a booklet or searchable online). That's the most direct mapping, since it's really just a scaled-down test to see how much acid gets to the pH you want -- the test is adding very diluted muriatic acid to a very tiny pool that happens to be full of pH reagent in it already so you can see the results immediately

But we don't usually recommend bothering with that test. It's a good tool for pool servicers who can't wait around and more often come across out-of-range pools. I have a set that came with my Taylor kit but have never used it, and I think that's true of most here, because A) it's pretty easy for us to add some and test again in an hour and B) we're testing often enough that it's very rare to be above 8.0 by some unknown amount. In most cases, I test every few days seeing it go up slowly until it finally hits 8.0, then I add a quart of MA.

I'll let others comment, but I wouldn't worry about the TA right now; 60 is within the recommended range. If you're adding in front of a return jet, you can add chlorine then acid relatively close in time -- I might wait 5 minutes for any fumes in the air to clear, but the chemicals dilute very quickly in the water.

 

[BullishBear]

Thank you @ajw22 @jmastron. Makes total sense. I have done the deed today! pH is brought down to 7.6-ish (it's in between 7.6 and 7.7) and in the best value per TFP's recommendations for SWG + Plaster pool. I did not touch TA and probably I noted incorrect value above because the addition of dry stabilizer (CYA) few weeks back has bumped TA as well. Today, I tested it to be almost turned and briefly stayed red at 70 and then flipped back to green in 2 seconds so on the 8th drop the color turned and stayed red so TA is 80 (or 75ish) which is again the top end of the recommended range.