New borate drop test at piscines-apollo vs. test strip

MyAZPool

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New borate drop test at piscines-apollo vs. test strip

:goodpost: Matt, Just found your post.

Thanks so much for this information to include the links to obtain the added supplies etc.

I haven't tried it yet but I will, just as soon as I can get the additional items that I need. I am excited to try it and be able to more accurately determine the borate level in my pool.
 
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Hal3

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Jul 29, 2008
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I was just looking at the borate test threads. I just ordered these:


 
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geh

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Nov 28, 2020
106
New Orleans
This is great. I finally got all the materials and my borate tested at 36ppm which is around where I suspected it would be. So My pool math calculator is telling me 4 boxes of Borax for my volume pool (roughly 15,600 gal.) to bring it up around 50ppm.

One question: I have this dropper with .5ml and 1ml markings and don't know where it came from. Is that for the bromythol bottle? It must have come with something, just can't remember. Does it serve any useful function for this test?
 

JoyfulNoise

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Does it screw onto the bottle? Some bottles are shipped capped with separate dropper.

If you add borax, you will need to add muriatic acid as well. Borax is a strong base and will raise pH very quickly. Boric acid is a weak acid so it doesn’t drop pH very much when adding large quantities. I prefer to use boric acid, it’s a lot easier.
 

geh

Gold Supporter
Nov 28, 2020
106
New Orleans
Yes, its a screw cap dropper. I'll use it for other things. I brought my Ph down to 7.0 before I added the borax so I expect it will be around 8.0 today, and will bring down accordingly. I used boric acid last time and this is a top-off and it was in the store so I just got the borax. Thanks for the testing process. The strips were hard to differentiate the color gradations.
 

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geh

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Nov 28, 2020
106
New Orleans
The 4 boxes of 20 Mule Borax brought my borates up to 48ppm according to your test. That's about right. My pH went up a bit over 8.0, from the 7.0 that I recorded just before adding the borax. Using the Taylor acid demand test it called for 3.75 quarts of muriatic acid, and at this point I had only .5ppm FC. Seems the results of the Taylor tests were inaccurate with the water being this out of balance (or maybe I tested too early and needed a day for things to stabilize). So I added a gallon of LC and 3.5 quarts muriatic. Today everything tested beautiful, with the Ph being a little higher than I would like, but right within range:

FC 3.8
CC 0
pH 7.8
TA 80
CH 470
CYA 40
BOR 48

Going to add 2 cups muriatic to bring the pH down to 7.6, and 2 cups LC to bring the chlorine up to about 5ppm, but those are just tweaks to what I think is pretty well balanced water. I also may had some dry stabilizer to bring my CYA up to 50, because for one, we have hot sun here burning up the chlorine, and also have had record rainfall this year causing a fair amount of water exchange so far, bringing the CYA down progressively.
 
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riny

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Some of the products mentioned earlier are no longer available, so here's an updated shopping list for 2021 (these are all available with Prime in a day or two, in my area at least):
  1. Beaker
  2. BTB
  3. Mannitol
Total cost was under $30. The diameter of this beaker is slightly larger than the well in the SpeedStir but it sits on top and still works with no issues.

I added borates last week and couldn't be happier. The water is SO CLEAR and my pH is stable for the first time all summer. I used BioGuard Optimizer which is 100% boric acid (NOT Optimizer Plus, which is something else). It just gets dumped in the skimmer, dissolves quickly, and there's no need to add acid. The only weird part for me is that the borate level came out higher than I was expecting.

According to Pool Math, it would take 26 lbs of boric acid to raise my level to 50. It's already late in the season so I bought a 20 lb tub, and PM says this should have gotten me to 38. But I did the drop test twice, on two different days and with different lighting conditions, and got 60 both times. I have no complaints about this but I did find it curious.

One other thing I'll add: reading the instructions, the drop test sounds intimidating. But it's actually REALLY easy. I can make a short video if anyone is interested in seeing it.
 

ArsenalFan

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After discussion with fellow member smackdab, it was decided that the test should be re-written to be more clear especially in light of some of his recent data on thiosulfate reductions of chlorine (dechlorination). See HERE - R-0007 FC drop in a sample size .

Equipment Needed
SpeedStir (is really, REALLY useful!!!)
50mL Beaker* (can be purchased on Amazon HERE)
A 1/8th teaspoon measure (can be purchased on Amazon HERE)

*The 50mL beaker can sit on the SpeedStir allowing easy mixing of reagents

Chemicals Needed
Taylor R-0007 - Chlorine neutralizer reagent
Taylor R-0009 - Sulfuric acid reagent
Taylor R-0010 - Sodium hydroxide calcium buffer reagent
Bromothymol Blue (BTB) - (See Post #134 where I show two different manufacturers)
Mannitol Powder - From Amazon HERE

Test Procedure (50mL Water Sample)***
1.) Collect a 50mL sample of pool water
2.) Add 2 drops of R-0007 to neutralize the chlorine
3.) Add enough BTB until the water turns to an easily visible blue color. The volume of BTB applied here will not affect the results of the test; it's just an indicator.
4.) Add enough R-0009 drop-wise to lower pH. You want the indicator dye to transition from blue to blue-green to yellow-green to straw yellow. Straw-yellow is the color one wants to see and it should take anywhere from 8-12 drops to get there depending on your starting pH and TA.
5.) Now add approximately 2 drops of R-0010 until the water just turns pale blue. This is the hard part - you want to get the indicator dye to just turn blue, like a baby-blue and not go all the way back to a deeper blue. Typically 2 drops is all that is needed.
6.) Add 2 level spoonfuls (1/4 teaspoon total) of Mannitol. If the water has boron in it, then the sample will turn yellow again.
7.) Add R-0010 drops until the water transitions from straw yellow to greenish-blue to baby blue, i.e., similar shade of blue from Step 5. Record how many drops 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 4ppm/drop in units

***Please note - This test protocol was done using my pool water where the following was present -

FC: 6ppm
CC: 0ppm
TA: 60ppm
CYA: 90ppm
pH: 7.6
CH: 1150ppm
Borate: ~ 56ppm
Temp: 85F
Salt: 3800ppm

Alternative Test Method Volumes

For a 25mL sample, each drop of R-0010 used only in step 7 equals 7.9ppm
For a 25mL sample, you will likely only need 1 drop of the R-0007


Notes:

*Dechlorinating the sample is important. The bromothymol blue (BTB) dye is sensitive to chlorine and will be bleached by it. 2 drops of R-0007 is usually more than enough for FC in normal ranges.

*If your pool water has high levels of TA (>100 ppm), I would suggest experimenting with the the number of drops in Step 4. It is important to get the sample down below the transition point for the BTB indicator and a high TA water sample might make it necessary to use a few more drops of R-0009 (See smackdab's analysis HERE). The presence of high TA will not affect the end result.

*The amount of bromotymol blue (BTB) used in Step 3 should be adjusted to give you the best color shade you can see. The standard BTB bottles in the chemical section don't use dropper tips but are rather more like squeeze bottles. So just add enough BTB so that you can see the colors.

*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.

*Yes, you have to try to remember the shades of blue unfortunately. This is a titration test where you are trying to measure something called the "equivalence point", i.e., the exact pH value where there's a sharp transition from yellow to blue. This is very easily see with a pH probe (which is what you would use in a lab) but it's much harder to do with a visual color determination. So what you're really after is that exact point when the BTB changes from a greenish-blue color to baby-blue as that is the point in the pH curve where the sharpest change occurs. If anyone is interested in the chemistry details, this website has a decent explanation -

Titration Fundamentals - Chemistry LibreTexts
Matt,
Thank you, so much for posting this procedure. I finally got tired of the strips so purchased what I needed and did my Borate test. I was getting 70ppm with the Taylor Strips and LAmotte 50. You guessed it I am right in the middle 60
 
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ArsenalFan

Silver Supporter
Jan 29, 2021
48
Brea, CA
Pool Size
18250
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Plaster
Chlorine
Salt Water Generator
SWG Type
CircuPool Core-55
Some of the products mentioned earlier are no longer available, so here's an updated shopping list for 2021 (these are all available with Prime in a day or two, in my area at least):
  1. Beaker
  2. BTB
  3. Mannitol
Total cost was under $30. The diameter of this beaker is slightly larger than the well in the SpeedStir but it sits on top and still works with no issues.

I added borates last week and couldn't be happier. The water is SO CLEAR and my pH is stable for the first time all summer. I used BioGuard Optimizer which is 100% boric acid (NOT Optimizer Plus, which is something else). It just gets dumped in the skimmer, dissolves quickly, and there's no need to add acid. The only weird part for me is that the borate level came out higher than I was expecting.

According to Pool Math, it would take 26 lbs of boric acid to raise my level to 50. It's already late in the season so I bought a 20 lb tub, and PM says this should have gotten me to 38. But I did the drop test twice, on two different days and with different lighting conditions, and got 60 both times. I have no complaints about this but I did find it curious.

One other thing I'll add: reading the instructions, the drop test sounds intimidating. But it's actually REALLY easy. I can make a short video if anyone is interested in seeing it.
I just got all these from Amazon:
 
Aug 15, 2021
5
Houston, TX
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-45
Looking to add borates now. If I purchase more boric acid than Pool Math says is needed for 50 ppm, can I store the remainder of the boric acid for extended periods? If so, must it be stored indoors? I assume it will.
 

PoolStored

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Jun 24, 2021
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Looking to add borates now. If I purchase more boric acid than Pool Math says is needed for 50 ppm, can I store the remainder of the boric acid for extended periods? If so, must it be stored indoors? I assume it will.
Duda Diesel Boric acid comes in what is *like* a 5 gallon pail with top. Stores extremely well. I think it would survive being outdoors. I need 75 lbs for 50ppm, comes in 50-55 lb (don't remember), so I had leftovers. Have remainder sealed in pail from Duda. Fairly air tight. Have in shed and stores well.
 
Aug 15, 2021
5
Houston, TX
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-45
Duda Diesel Boric acid comes in what is *like* a 5 gallon pail with top. Stores extremely well. I think it would survive being outdoors. I need 75 lbs for 50ppm, comes in 50-55 lb (don't remember), so I had leftovers. Have remainder sealed in pail from Duda. Fairly air tight. Have in shed and stores well.
Thank you! I was looking to buy 2 55-lb jugs from them. Need 86 lbs to start.
 

JoyfulNoise

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Best to store it indoors. My pail has about 10lbs or so in it and I keep it in my garage (near freezing to 130F temp swings throughout the year). It’s well over 6 years old. It doesn’t degrade.