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

  1. Back To Top    #121

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

    Thanks, SunnyBlues.

    You have been reading and learning a LONG time to remember all those experts. Thanks for your testimonial.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
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  2. Back To Top    #122

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

    Quote Originally Posted by bobodaclown View Post
    ...

    All 3 (mannitol, Ideal (xylitol), and erythritol) turned the water yellow as expected in step 6.

    In step 7 the mannitol and Ideal had the same drop count. The erythritol had a drop count of only 4 till it was the same shade of blue.

    First I ran the test with the mannitol, using 25ml., got the drop count of 6. to the same shade. That was my base line. Second was the erythritol drop count was 5, and third was the Ideal, drop count of 6.

    This was a limited run and only using 25ml.

    One of the issues using the Ideal, is we don't the percentages of Xylitol, maldodextrin and sucralose in the mix. Sorry I don't have straight Xylitol.

    Hope someone finds this useful.
    Awesome, thank you. Ive ordered some Xylitol for ~AU$25 delivered.
    Steve.
    30,000L (8,000g) Pebblecrete | Davey 3sp Eco pump | Poolrite sand filter & SWCG |
    Waterco solar panels & Astral E140 pump| K2006, BlueDevil pH, Salt meter & K1766 | Town water - pH 7.2, TA 50, CH 60 | Esky full of coldies |

  3. Back To Top    #123

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

    Quote Originally Posted by JoyfulNoise View Post
    ...OR, if you want to be really accurate about it, you can use two beakers side by side and truncate the first test after you get the initial blue shade and then do the full test protocol on the second beaker to match it with. Takes more time, but it works well.
    Thats what I was planning on doing, I guess I have to be careful to use the same amount (drop count) of BTB in each?

    I've got my xylitol crystals from NuNaturals, via eBay. It contains traces of silica. Not sure if crystals or the silica will affect the test?

    I'm not sure if I'm reading this correctly but unlike mannitol that complexes with borate in a 2:1 ratio, the abstract from this paper Reactions of Polyols with Boric Acid and Sodium Monoborate | SpringerLink suggests to me that xylitol complexes in a 1:1 ratio. Suggesting that I only need half the amount? Think I'll go for the full amount for now.

    I've got my beakers, BTB, Taylor reagents and my speedstir arrived today. Waiting on the fancy stainless 1/8th teaspoon, ~$5 with free standard shipping from the US or $300 for express - I went for the standard.

    I tried a mannitol search again in eBay and I have a winner, 100gms @ 99.9% pure for US$20 from China. So I guess I'll be able to do a side by side comparison.

    Quote Originally Posted by JoyfulNoise View Post
    ...
    Now, what I did not tell you is that I have borates in my pool water which acts as a mild algaestat (it inhibits algae growth) AND I treat for phosphates every season (my current PO4 levels are 0ppb). Both of those conditions make my water much less "reactive" to algae, that is to say, even if algae found it's way into my water the low nutrient conditions (low PO4) and presence of the algaestat (boron levels ~ 50ppm) mean that the algae can not efficiently grow. In real terms that means that algae replication rates are slower giving chlorine much more margin to act as a sanitizer.
    ...
    Slightly off topic but it begs the question, 'why 50ppm borate?' What's your thoughts on raising it to 60 or even 70ppm? Would there be any significant benefits from a pH buffering point of view, particularly within the SWG cell?
    Steve.
    30,000L (8,000g) Pebblecrete | Davey 3sp Eco pump | Poolrite sand filter & SWCG |
    Waterco solar panels & Astral E140 pump| K2006, BlueDevil pH, Salt meter & K1766 | Town water - pH 7.2, TA 50, CH 60 | Esky full of coldies |

  4. Back To Top    #124
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    Re: New borate drop test at piscines-apollo vs. test strip

    Quote Originally Posted by AUSpool View Post
    Thats what I was planning on doing, I guess I have to be careful to use the same amount (drop count) of BTB in each?

    I've got my xylitol crystals from NuNaturals, via eBay. It contains traces of silica. Not sure if crystals or the silica will affect the test?

    I'm not sure if I'm reading this correctly but unlike mannitol that complexes with borate in a 2:1 ratio, the abstract from this paper Reactions of Polyols with Boric Acid and Sodium Monoborate | SpringerLink suggests to me that xylitol complexes in a 1:1 ratio. Suggesting that I only need half the amount? Think I'll go for the full amount for now.

    I've got my beakers, BTB, Taylor reagents and my speedstir arrived today. Waiting on the fancy stainless 1/8th teaspoon, ~$5 with free standard shipping from the US or $300 for express - I went for the standard.

    I tried a mannitol search again in eBay and I have a winner, 100gms @ 99.9% pure for US$20 from China. So I guess I'll be able to do a side by side comparison.



    Slightly off topic but it begs the question, 'why 50ppm borate?' What's your thoughts on raising it to 60 or even 70ppm? Would there be any significant benefits from a pH buffering point of view, particularly within the SWG cell?
    I'm going to start charging you for all the quoting you're doing

    I've always started my pool at 60ppm every season just to keep above 50ppm with splashout. I'm usually down to 46ppm by the following year so I lose about 14ppm year over year. I think I still have 15-20lbs of boric acid in my tub in the garage.

    The pH buffering won't get all that much better. Maybe a marginal improvement. The algaestatic properties get a fair bit better at 100ppm and significantly better at 200ppm but then your pushing the limit at which you could make, and I say "could" make a small child or beloved animal companion sick.

    So 50ppm has a very nice safety margin built into it. Anything up to 100ppm is fine if kids and dogs aren't around but you have to promise not to use the pool water to make ice cubes for the Margarita Machine....


    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

  5. Back To Top    #125

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

    Excellent, thanks. I'm sure I've read somewhere that the EPA's limit for borates is 50ppm but I cant find anything.

    For the record I've just had my first go at the 'Xylitol test for borates' and think it went well. Followed the Mannitol test instructions as close as possible. To start with my pool is out of 'balance'. The swim season is over for us and the water temp has dropped to 20oC, I haven't tested or adjusted my SWG for a little while and it appears I've been SLAMing my pool.

    Current levels;

    Salt: 4700ppm
    Temp: 20oC
    FC: 15ppm
    CC: 0
    pH: 7.8
    TA: 120ppm
    CH:475ppm
    CYA: 60ppm
    Borates - LaMotte strips: 30ppm
    Borates - Xylitol Mannitol test: 36ppm

    Notes:
    I've gone for a 50ml sample. With high FC I've gone with 4 drops of R-007.

    The instructions on my BTB says 10 drops in 15mls so I've used 10 drops of BTB.

    First attempt. First 50ml sample; 4 drops of R-007, 7 drops of R-009, 10 drops of BTB. Sample was blue.

    Second attempt. Second 50ml sample; 4 drops of R-007, 9 drops of R-009, 10 drops of BTB. Sample was still blue. Added 6 more drops of R-009 until the sample went past green to a nice yellow. Added two drops of R-0010, the sample turned light blue at the first, then slightly darker at the second. Stopped and kept sample for comparison.

    Third 50ml sample; 4 drops of R-007, 15 drops of R-009, 10 drops of BTB, nice yellow colour. 2 drops of R-0010 and got blue the same as before. Added 1/4tsp of Xylitol crystals and got a nice clear yellow but had to wait a little for the crystals to dissolve. Drop wise of R-0010 to the same colour of sample 2 - 9 drops, 36ppm.

    I'm still waiting on my Mannitol and will run both Xylitol and Mannitol when it arrives but for now I think the Xylitol works just fine. While I'm waiting for the Mannitol I'll work on reducing my FC and TA. And adjust my borates to 50ppm.
    Steve.
    30,000L (8,000g) Pebblecrete | Davey 3sp Eco pump | Poolrite sand filter & SWCG |
    Waterco solar panels & Astral E140 pump| K2006, BlueDevil pH, Salt meter & K1766 | Town water - pH 7.2, TA 50, CH 60 | Esky full of coldies |

  6. Back To Top    #126
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    Re: New borate drop test at piscines-apollo vs. test strip

    Nice results!! The number of drops of R-0009 needed will be related to your TA as the point of the R-0009 is to drop the pH to low value so the BTB can work (pH range is 6.0-7.6). If you have a lot of TA, you need more R-0009 to get to the right pH level.

    Look forward to the side-by-side comparison.


    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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

    Thanks.
    Does it matter when I add the BTB, obviously after the R-007 but before the R-009 and then add the R-009 dropwise to achieve a clear yellow?

    ie.
    50ml sample.
    3-4 drops R-007 (FC determined, high or low)
    10 drops BTB (ten drops worked well for me#)
    R-009 dropwise to a full yellow
    1 drop of R-0010 to light blue - second drop if blue is not achieved with first.
    1/4tsp Xylitol - ensure Xylitol is fully dissolved.
    R-0010 drop wise to light blue from before. 1 drop = 4ppm

    I found that the initial blue target prior to the xylitol addition fades a little after a few moments then becomes stable. [Edit. When titrating with the R-0010 my 8th drop was not quite enough and the 9th maybe a bit too far but after a few moments it faded back to a perfect match. Edit]

    Preparing a sample and stopping after step 5 for colour reference really helped, particularly for the first go.

    #10 drops of BTB gave me a colour I could easily see. As before, the instructions say 10 drops in a 15ml sample for pH essay so maybe I could go as high as 30 drops of 0.04% in a 50ml sample but there's no point since I can clearly see the colour change at 10 drops. I have ordered some 0.1% BTB, totally unnesarsary since the 0.04% works just fine, but I'll give it a go starting at maybe 6 drops? My 0.04% BTB is a 45ml/1.5fl oz, small but enough for years of testing and I had no trouble with the dropper.

    My BTB instructions give the pH transition as;
    Yellow pH6.4.
    very light green pH6.6
    light green pH6.8
    light dark green pH7.0
    dark green pH7.2
    light blue pH7.4
    full blue pH7.6

    Edit: love the SpeedStir, wish I'd invested in that from the start. Have to be cautious with rinsing and sample sizing though. I discard into a sink strainer, rinse in tap water, rinse in pool water three times and dry with paper towel. I always rinse three times then collect my sample from about an arm length down. Add the sinner to the correct sample size after collection. Rinse in tap water for storage.
    Steve.
    30,000L (8,000g) Pebblecrete | Davey 3sp Eco pump | Poolrite sand filter & SWCG |
    Waterco solar panels & Astral E140 pump| K2006, BlueDevil pH, Salt meter & K1766 | Town water - pH 7.2, TA 50, CH 60 | Esky full of coldies |

  8. Back To Top    #128
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    Re: New borate drop test at piscines-apollo vs. test strip

    Hi guys wondering if this Bromothymol would work? Its the 0.04%

    https://www.amazon.com/LabChem-LC120...lue%2C+0.04%25

    SWG 31K Gallon 20X41 Vinyl Inground Pool

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

    Yup. That should work.


    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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

    Quote Originally Posted by Gags80 View Post
    Hi guys wondering if this Bromothymol would work? Its the 0.04%

    https://www.amazon.com/LabChem-LC120...lue%2C+0.04%25
    Doesn't look like it has a dropper tip, you may need a pipette to use it.
    Steve.
    30,000L (8,000g) Pebblecrete | Davey 3sp Eco pump | Poolrite sand filter & SWCG |
    Waterco solar panels & Astral E140 pump| K2006, BlueDevil pH, Salt meter & K1766 | Town water - pH 7.2, TA 50, CH 60 | Esky full of coldies |

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

    My Mannitol finally arrived and I've tested my pool water and a 50ppm borate standard solution using both the mannitol (99.9%) and xylitol crystals (~99%*). I used PoolMath to prepare the borate standard solution with 2.86g in 10L of tap water (TA 50ppm, CH 60ppm) and tested that using both mannitol and xylitol. Since the last borate mannitol test using xylitol I've added enough boric acid to raise my borates to 55ppm, FC has been reduced to 7.5ppm and TA to 70ppm.

    The LaMotte test strips measured both the pool water borate and 50ppm standard solution in the 50ppm range. My results were: 32ppm with 2 1/8tsp scoops of mannitol (0.48g), 56ppm with 3 1/8tsp scoops of mannitol (~70g) and 56ppm with 2 1/8tsp scoops of the xylitol (89g) for the pool water samples, 44ppm with 3 scoops of mannitol and 48ppm with 2 scoops of xylitol for the standard solution.

    I found that retaining the the first sample for colour comparison didn't work as the blue colour faded to a blue green after a while; indicating a drop in pH I think? After a few goes I thing I was able to easily remember the right shade of blue. Or rather, I could identify the drop that had gone too far.

    I don't know why, but my results indicate that 2 scoops of mannitol wasn't enough. My mannitol may have a lower density, ground finer? Three scoops of my mannitol is almost equal to two scoops of xylitol by weight. My results for the pool water samples using both mannitol and xylitol where identical and inline with what was expected given the last xylitol test result and the increase expected after boric acid additions from PoolMath recommendations.


    My current pool water test results;
    FC 7.5ppm
    pH 7.8
    TA 70ppm
    CH 430ppm
    CYA 75ppm
    Salt 4600ppm
    Bor 56ppm

    I made the 50ppm borate standard from PoolMath using a 10,000L pool and dividing all amounts by 1000. Starting with 10L of carefully measured tap water which typically has 50ppm TA and 60ppm CH. I added 0.70g of CYA and 2.86g of boric acid. I also chlorinated it to ~5ppm by adding 1.5ml of 4% bleach. It had a pH of 7.2.

    50ml samples in 50ml beaker on the speedstir.
    R-0007 - 3drops. To neutralize the chlorine.
    R-0009 - 9drops. To lower pH and neutralize carbonate alkalinity.
    BTB - 10 drops. Pool water - Green. Standards - yellow.
    R-0009 - 6 extra drops to get full yellow, 3 for the standards.
    R-0010 - 2 drops.
    Retain sample for colour comparison.

    Retaining the initial sample seemed moot as the colour shifted with time so that idea was dropped.

    50ml sample in new 50ml beaker on speedstir.
    R-0007 - 3drops. To neutralize the chlorine.
    R-0009 - 7drops. To lower pH and neutralize carbonate alkalinity.
    BTB - 10 drops.
    R-0009 - 6 more drops to get full yellow.
    R-0010 - 2 drops.
    Mannitol or xylitol - 2 or 3 1/8tsp measures.
    R-0010 - drop wise to previous colour. Drops times 4 for ppm.

    *The ingredients for the Xylitol Crystals list only Xylitol crystals but does list silica as other ingredients so I've guessed at %99. I've emailed NuNaturals but they haven't responded yet.




    Steve.
    30,000L (8,000g) Pebblecrete | Davey 3sp Eco pump | Poolrite sand filter & SWCG |
    Waterco solar panels & Astral E140 pump| K2006, BlueDevil pH, Salt meter & K1766 | Town water - pH 7.2, TA 50, CH 60 | Esky full of coldies |

  12. Back To Top    #132
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    Re: New borate drop test at piscines-apollo vs. test strip

    AUSpool,

    Thanks for doing the experiments!! I will reread your writeup more carefully. One thing I wanted to note was the purpose of the initial R-0009 treatment. While it is true that the R-0009 is added to such an extent that it will use up all of the carbonate alkalinity, the primary purpose of it is to acidify the water to ensure that all of the borates are in the form of boric acid and that reacts more quickly with the diol groups. Also, you definitely want to add mannitol or xylitol or whatever diol being used in excess so that the reaction completely consumes all of the available boron. So if two scoops seems to be not enough, then use three scoops. I too have found the mannitol powder to be very "fluffy" and hard to scoop out. So I typically wind up adding about 3 scoops. One could calculate the exact weight of the mannitol needed, but it's probably best to just over do the mannitol addition a bit and not worry about it. I also agree that getting the starting and ending blue colors to match is probably the most difficult part of the test.
    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

  13. Back To Top    #133

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

    Thanks,
    I think it is awesome that you guys have invented your own test, that is really quite an achievement.

    <Edit: Please correct me if I'm wrong here; the R-0009 acidifies the sample then the R-0010 brings the pH back up but still low enough that all the borates are still in the form of boric acid? I did briefly think about a third test with 3 scoops just in case I'd missed some borates but suddenly needed three when my first result was 32ppm. My mannitol is white, fluffy and powdery while the xylitol is more like sugar crystals, weighing it was a bit of an after thought. I have enough now for a lifetime of testing. Edit>

    If nothing else, I'm confident that the xylitol works; as long as its quite pure. The xylitol I used is from NuNatrurals, Eugene, OR.

    I don't know if my 50ppm standard borate solution really helps but it gives me confidence that the 'borate mannitol / xylitol' test is quit acurite and at the very least, more accurate than the test strips. My results were on the low side and one less drop was needed for the mannitol but I think it is in the ball park or what they say, 'no significant difference'. My standard is garage than lab grade and may be a little low. Back at post #61, jaduck offered 1.13g in 1 gallon which is 2.985g in 10L. I don't know where that comes from but it would probably be enough the put my testing spot on the 50ppm mark.
    Last edited by AUSpool; 05-12-2017 at 06:52 AM. Reason: Added extra paragraph
    Steve.
    30,000L (8,000g) Pebblecrete | Davey 3sp Eco pump | Poolrite sand filter & SWCG |
    Waterco solar panels & Astral E140 pump| K2006, BlueDevil pH, Salt meter & K1766 | Town water - pH 7.2, TA 50, CH 60 | Esky full of coldies |

  14. Back To Top    #134
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    Re: New borate drop test at piscines-apollo vs. test strip

    Folks,

    Both of these bromothymol blue indicators work (I just tested side-by-side and got exactly the same results -



    I like the Hach product a little better as it has a 0.5/1 mL measuring eye dropper in it. It also is not water based but isopropyl alcohol based as BTB is more soluble in alcohol than water. The indicator color in the bottle is more green/yellow than the blue water based BTB from Consolidated Chemicals. Amazon link here -

    https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

    It's also a bit more expensive but I noticed the other BTB was fluctuating in availability so I wanted to post up an alternative.

    As a side not, I just added 10lbs of boric acid to the pool to up my borates to 56ppm as they were down to 44ppm.

    Happy borating......
    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

  15. Back To Top    #135
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    New borate drop test at piscines-apollo vs. test strip

    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 [B] 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
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

  16. Back To Top    #136

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

    I followed the directions above to test my borate level. My test results:

    FC: 7ppm
    CC: 0ppm
    TA: 70ppm
    CYA: 50ppm
    pH: 7.5
    CH: 325ppm
    Borate: ~ 50ppm
    Temp: 84F

    1.) 50ml sample.
    2.) 2 drops of R-0007 dechlorinates 8ppm FC.
    3.) 10 drops of BTB 0.04% to get a pale blue.
    4.) 9 drops of R-0009 to lower the pH and turn the sample straw yellow.
    5.) 2 drops of R-0010 to get a pale blue.
    6.) I used my plastic measuring spoon to mix 1/4 teaspoon mannitol powder into the sample. I don't have a speed stir. Its kind of hard to dissolve the powder by swirling by hand, plus it cleaned my spoon.
    7.) 12 drops of R-0010 to turn back to the same shade of blue = 48 ppm. Since adding 50 ppm borates, I had to drain about an inch out of the pool plus had kids swimming a few days so I'd say that is pretty much on the money.
    16k AG Vinyl Sand Filter

  17. Back To Top    #137
    JoyfulNoise's Avatar
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    Re: New borate drop test at piscines-apollo vs. test strip

    Quote Originally Posted by smackdab View Post
    I followed the directions above to test my borate level. My test results:

    FC: 7ppm
    CC: 0ppm
    TA: 70ppm
    CYA: 50ppm
    pH: 7.5
    CH: 325ppm
    Borate: ~ 50ppm
    Temp: 84F

    1.) 50ml sample.
    2.) 2 drops of R-0007 dechlorinates 8ppm FC.
    3.) 10 drops of BTB 0.04% to get a pale blue.
    4.) 9 drops of R-0009 to lower the pH and turn the sample straw yellow.
    5.) 2 drops of R-0010 to get a pale blue.
    6.) I used my plastic measuring spoon to mix 1/4 teaspoon mannitol powder into the sample. I don't have a speed stir. Its kind of hard to dissolve the powder by swirling by hand, plus it cleaned my spoon.
    7.) 12 drops of R-0010 to turn back to the same shade of blue = 48 ppm. Since adding 50 ppm borates, I had to drain about an inch out of the pool plus had kids swimming a few days so I'd say that is pretty much on the money.
    GET.
    A.
    SPEEDSTIR!

    (You'll thank yourself later)

    Congrats on successfully testing for borates. I have very fine, fluffy mannitol powder that tends to fly all over from static charge from the plastic bottle. Thankfully mannitol is completely non-toxic and a great coffee sweetener

    I've often thought of making a saturated mannitol solution for use as a substitute instead of powder. I haven't done the calculation but it should work if the saturation concentration is high enough.


    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

  18. Back To Top    #138
    HOO's Avatar
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    Re: New borate drop test at piscines-apollo vs. test strip

    I've been wanting to find a usable borate drop test for a while now and have been following this borate testing thread with interest. I tried something today that I'm surprised no one has written about. I bought a pH meter and used it to perform the test with some slight changes: I don't need to neutralize the chlorine nor do I need the indicator solution. With a 50ml sample, the steps I used are:

    1. Lower the pH to around 6.0 (R-0009) (I picked this number because that is where the BTB would be yellow)

    2. Raised the pH (R-0010) to around 8.2 and recorded that number (the point where the BTB would be blue

    3. Added the 1/4 teaspoon of Mannitol

    4. While constantly stirring, I added the R-0010 drop by drop while recording the pH rise

    5. When the pH reached my starting point that I recorded in step 2, I used the conversion factor of 4 x drops to get my borate ppm

    The rise in pH was linear (0.1 pH change per drop) until I was approaching the end point at which time each additional drop produced a larger and larger pH change. I was hoping that the pH rise rate would be linear and a simple borate ppm calculation could be performed just knowing the starting and ending pH. Perhaps someone could come up with a formula that would account for the pH curve. I would be nice to stick two numbers into a formula and have the borate ppm calculated.

    Anyway, I wanted to share this with you and see what your thoughts might be on my test method. At the very minimum I can throw away my Phenol Red and use my meter to test the pool pH. As a side note, I have played around with Clear Waters Testing's borate test kit sold on E-bay. I've had several conversation with Chris at the company and helped him find some problems with his reagents. I still have an issue getting what I think are accurate results with his procedure, but I have a couple of additional things I want to try before I contact him again.


  19. Back To Top    #139
    JoyfulNoise's Avatar
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    Re: Borate Drop Test Revived

    Sorry, Tapatalk screwed up some of my notifications a few days ago. Sorry I did not see your post.

    I'm on the road but will respond to your post later. It is possible to do the titration with a pH probe but the way you're doing it is wrong. I'll comment later.

    Also, I will have this post put back under the correct thread.

    Matt


    Merged this post back into the main thread, by request. jblizzle
    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

  20. Back To Top    #140
    JoyfulNoise's Avatar
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    Re: New borate drop test at piscines-apollo vs. test strip

    Quote Originally Posted by HOO View Post
    [FONT="]I've been wanting to find a usable borate drop test for a while now and have been following this borate testing thread with interest. I tried something today that I'm surprised no one has written about. I bought a pH meter and used it to perform the test with some slight changes: I don't need to neutralize the chlorine nor do I need the indicator solution. With a 50ml sample, the steps I used are:

    1. Lower the pH to around 6.0 (R-0009) (I picked this number because that is where the BTB would be yellow)

    2. Raised the pH (R-0010) to around 8.2 and recorded that number (the point where the BTB would be blue

    3. Added the 1/4 teaspoon of Mannitol

    4. While constantly stirring, I added the R-0010 drop by drop while recording the pH rise

    5. When the pH reached my starting point that I recorded in step 2, I used the conversion factor of 4 x drops to get my borate ppm

    The rise in pH was linear (0.1 pH change per drop) until I was approaching the end point at which time each additional drop produced a larger and larger pH change. I was hoping that the pH rise rate would be linear and a simple borate ppm calculation could be performed just knowing the starting and ending pH. Perhaps someone could come up with a formula that would account for the pH curve. I would be nice to stick two numbers into a formula and have the borate ppm calculated.

    Anyway, I wanted to share this with you and see what your thoughts might be on my test method. At the very minimum I can throw away my Phenol Red and use my meter to test the pool pH. As a side note, I have played around with Clear Waters Testing's borate test kit sold on E-bay. I've had several conversation with Chris at the company and helped him find some problems with his reagents. I still have an issue getting what I think are accurate results with his procedure, but I have a couple of additional things I want to try before I contact him again.

    [/FONT]

    So acid-base titrations (which is basically what the borate drop test is) are NOT linear, titration curves are always S-curves. In the case of borates, you are essentially titrating a weak acid (the boron-diol reaction) with a strong base (R-0010, sodium hydroxide). And so what you would measure using a pH probe is the pH response while adding a known volume of strong base. See this link for a quick primer on titration problems -

    https://www.khanacademy.org/test-pre...tration-curves

    In the process of determining the borate concentration, you would need to plot pH as a function of titrant volume added and then you look for what is known as the equivalence point - essentially the point at which the pH curve has it's steepest slope (one can mathematically determine this with great precision by using the first and second derivatives of the pH-volume curve). Once you know the location of the equivalence point, the unknown concentration can be calculated by knowing how much titrant was added, the volume of the test solution and the pKa of the reaction. However, it is doubtful anyone would want to do this type of analysis at home because you need to have very exact quantities of solution and titrant know which requires graduated cylinders, beakers and a volumetric buret capable of measuring micro-liter volumes of titrating solutions.

    The reasons why the drop based test using visual indicators is better is because -

    (a) The math has already been done to equate drop count with concentrations;
    (b) The visual equivalence point is easy to confirm with the BTB indicator because the transition from yellow to first baby blue is very close to the actual equivalence point
    (c) There's no need to own a pH probe or spend time calibrating it or purchase anything more complicated than couple of extra test solutions. The drop test uses most everything one already has in their kit.

    While I applaud your effort at home chemistry, you'd be better off just doing the test as it is outlined since it has been confirmed by multiple users of it as "accurate enough" for recreational pool purposes.
    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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