This is more specifically for Matt, aka Joyfullnoise, but anyone who is doing the test already works as well I also hope others trying it the first time may get some help with the same questions if they hit it.
I'll copy the instructions at the bottom or on a reply, but first the questions.
Here's me chemistry right at the time of the test, incase some of it could have effected my result:
FC - 6
PH - 7.1
TA - 40
CH - 80
CYA - 60
I've been waiting for the things I needed to test borates before touching PH or TA, but I need to get those fixed.
Anyway, I found the cleaned up instructions from Matt to be excellent!!! Big thanks to him, as well as all those in the old thread who took part in figuring it out. WAY over my head trying to read everything in the old one, lol.
On step 6 when I added the mannitol it BARELY turned yellow, or at least nowhere near to the yellow obtained in step 4. Is that ok, or should I use more powder next time?
On step 7 I hit a shade of blue just a TAD darker than the blue in step 5. Two drops at 7.9 is 15.8 if the above didn't skew it much. When I initially added last season I used the calculator and "should" have been around 50-55. However, with our 65 inches of rain a year on top of backwash and splashout the current level seems reasonable. On the test strips where I have all I can do to tell the difference between 0 and 80 I had guessed it to be around 25 so in the same ballpark.
Other than looking over my shoulder as I do it, does the above look correct? Specifically, step 6
- - - Updated - - -
1.) Collect a 25ml sample of pool water
2.) Add 2 drops of R-0007 to neutralize the chlorine
3.) Add 5 drops of R-0009 to lower pH and neutralize carbonate alkalinity
4.) Add 6 drops of BTB until the water turns yellow. You can use more than 6 drops if the color is too faint. The drop count here will not affect the results of the test.
5.) Add 2 drops of R-0010 until the water just turns pale blue. This is the hard part - try hard to remember the shade of blue here.
6.) Add 1 level spoonful (1/8 teaspoon) of Mannitol. If the water has boron/borates, then the sample will turn yellow again.
7.) Add R-0010 drops until the water turns into a similar shade of blue from Step 5. Record how many rops of R-0010 are used in this step.
8.) Calculate ppm boron/borates by multiplying the number of drops of R-0010 used only in step 7 by 7.9 for total ppm
Alternative Test Method Volumes
1.) Collect either 25ml or 50ml
8.) Calculate ppm boron/borates by using these formulas
For 25ml sample, each drop of R-0010 used only in step 7 equals 7.9ppm
For 50ml sample, you'll need 3 drops of R-0007 in Step 2, 7 drops of R-0009 in Step 3, 2 level spoonfuls of mannitol (1/4 tsp total) in Step 6 and each drop of R-0010 used only in step 7 equals 4.0ppm
*Dechlorinating the sample is important. The bromothymol blue (BTB) dye is sensitive to chlorine and will be bleached by it. 2 to 3 drops of R-0007 is usually more than enough for FC in normal ranges.
*If your pool water has very high levels of TA (>100 ppm), I would suggest experimenting with the the number of drops in Step 3. It is important to get the sample down below the transition point for the BTB indicator and a high TA water sample will make it necessary to use more drops of R-0009.
*The amount of bromotymol blue (BTB) used in Step 4 should be adjusted to give you the best color shade you can see. 6 drops of BTB is just a starting point, use more if needed.
*The R-0010 reagent (sodium hydroxide) has a very STRONG effect on raising the pH. So it should not take much to go from pale yellow to blue in Step 5. You don't want to overshoot this and add lots of R-0010 in this step. It would be easier if the R-0010 were less concentrated but we're stuck with what we have available.
*You can add extra mannitol powder as well. The point is to have excess mannitol powder in solution so that all of the boron reacts with it. Using too little will give you a false-low result.
*Yes, you have to try to remember the shades of blue unfortunately. This isn't a true "end point" titration but rather a color matching titration so there is a bit of subjectivity to it. I would suggest doing the test several times until you feel you are comfortable with it. So stock up on your R-0009 and R-0010 if you only have small quantities.