Hello All,
So my chemicals arrived last week for doing the titration drop test for boron. Here's what happened -
Water Chemistry Test (Taylor K-2006) -
FC = 5.8ppm
CC < 0.2ppm
pH = 7.6
TA = 60ppm
CH = 750ppm (ugh, this jumped up a lot from the winter time

)
Salt = 4000ppm
Temp = 88F
Test #1 :
So I first followed the procedure without first dechlorinating the 25mL sample. This was a total failure. I added the R-0009 (sulfuric acid) and then the bromothymol blue (BTB from now on) indicator and I could barely get a visible color. I even tried adding a few extra drops of the BTB indicator and I barely got yellow. I then added A LOT of the R-0010 Ca buffer and thought I got some hint of blue. Then I added the mannitol powder and there really was nothing there. So I stopped the test at that point.
Test # 2:
Added 2 drops of the R-0007 sodium thiosulfate drops to dechlorinate a 25mL water sample. Added 5 drops of R-0009 acid and then 6 drops of the BTB indicator (see note below on the difficulty of using the indicator dropper bottle). Obtained a solid yellow color. Added 2 drops of R-0010 (only needed 1) to go from yellow to blue. The second drop was accidental but I continued the test. I then added the Mannitol powder and the sample turned yellow again. Finally added R-0010 dropwise and got a count of 6.
Test #3 :
Repeat Test #2 above but only added 1 drop of R-0010 for the first yellow to blue transition. Results were then 7 drops to complete test and go from yellow to blue.
[EDIT]
I used the wrong factor in my original results. I used a 25mL sample size therefore the correct factor is 7.9ppm/drop.
Borate level result -
Test #2 :
Borate level result - 6 drops X 7.9ppm/drop = 47.4ppm
Test#3:
Borate level result - 7 drops X 7.9ppm/drop = 55.3ppm
[END-EDIT]
Summary -
I definitely needed to dechlorinate the sample in order to get the test to work as described. I don't know if the R-0007 is the best approach or if using a drop of peroxide would be better so that could be a future test. The results of Test #2 and #3 are reasonable as I added borates last summer using boric acid powder based on PoolMath results and I have had several good water exchanges between then and now (at least two full filter cleanings and a 3" drop in water level from an expected storm that never materialized as well as a few minimal drains from winter rains). [EDIT] So getting those results of is definitely in the ball park of reasonable. [END-EDIT]
This is just a personal observation but I found the BTB indicator solution I bought on Amazon to be very difficult to work with. The bottle is huge (60mL) and it is very difficult to squeeze out a single drop. I had to be very ginger in my handling of the bottle and make sure that I squeezed out drops very slowly to get it right. I also noted that I got better color if I used 6 or 7 drops as opposed to 5 drops. Since it's just an indicator dye, the number of drops used should not have an effect on the transition point, just the color intensity. The BTB indicator solution is very watery as opposed to some of the other dyes we use so squeezing a single droplet is very tricky. Perhaps a commercial formulation for a product would use a more concentrated BTB solution or an additive to help increase the viscosity of the indicator solution to make droplet formation easier.