Acid demand test

Terry

0
Jul 8, 2008
130
Dallas, Tx
Hoping someone can help me to get a better understanding of the Taylor Acid demand test and the reagents needed to run it. I have a new pool going in that I plan to do a bicarb startup on, and would like to be able to run the acid demand test. Once upon a time, many years ago, I had a test kit that ran the acid demand test, so I've done it before, but same as the kit is long gone, so is much of my recollection.

The test kit I use now is relatively similar to the TF100, but was put together with parts of different kits I have acquired over the years. The pH test I use is the HTH comparator, which I believe is the same as the K1000.

What I *think* I know:
-The Taylor reagent for the Acid demand is R0005.
-The comparator tube I use will not work.
-I think the K2006 pH test uses R0004. I have a bottle of R0004 picked up accidentally to replace my R0014.

What I need to know:
-If I run the pH test in one of my 25mL tubes what volume of water do I use?

-I realize I won't have a color comparator (or maybe I do, does my K1000 comparator have the same colors?), but is that important if the point of the test is to determine the acid demand?

-Does the K2006 pH test run the same way: x volume of water, add 5 drops of R0004? Do I need any cl neutralizer, etc?

-How do I run the acid demand portion of the test? It's been many years, but what I remember, you save the pH test and then add the reagent (R0005, right?) drop by drop to determine the amount of acid needed. What is my endpoint- clear, or another color change? What is my multiplier? Or, if I have absolutely no recollection of how to do this test, how do you do it?


I realize that the Pool Calculator can give me a volume of acid to add, but also realize that is dependent on my interpreting the initial pH reading correctly. A few weeks ago I helped a local TFP new pool owner get his new pool up and going and we each interpreted the pH reading to be 8.4, independently, using our own test kits. Turned out, based on the amount of acid needed to get it into range, it was closer to 8.7. Lesson learned, above 8.2 and I'm guessing what the pH actually is.
 
I use it and like it for two reasons:

1. You just do the calculation once to figure out how much acid for each drop of acid demand reagent needed for your size pool. No need for Pool Calculator, Tables, or fingers after that. (For me, one drop acid demand = 1/3 jug of MA)

2. You can do your color comparison in the orange/yellow/barely red zone of the comparator rather than the red/redder/reddest part which I personally find challenging.
 
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