Testing for Borate Concentrations

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ThatOneExcelGuy

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Jun 8, 2023
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South Carolina
I am considering using borates in my pool but I have yet to find a test kit that meets the criteria for me.

My favorite water tests are hands down drop titrations. I find them the most accurate and while I’ve thought about it I have yet to splurge on a colorimeter. I’d love to figure out how to use my spectrophotometer as a pool colorimeter but I can’t find the exact math/procedures (if anyone has any tips I’d be pleased to hear them).

Taylor makes a boron drop test kit, but I do not believe or at least am not confident enough that it would accurately measure borate concentration. Has anyone used it?

Are my options really only between strips and a colorimeter?

Thanks
 
A mannitol test for borates has been developed by some creative members. It is a bit complex and you can read about it here.

A commercial Borate Alkalinity Test Kit is available. This kit is similar to the TFP mannitol test process but keep in mind that the manufacturer has designed their test around industrial/consumer water sources that DO NOT contain a strong oxidizer like chlorine. So you may have problems with their test method if you don’t first neutralize the chlorine in your sample water.

Borates in pool - Further Reading

www.troublefreepool.com www.troublefreepool.com
 
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ThatOneExcelGuy said:
I am considering using borates in my pool but I have yet to find a test kit that meets the criteria for me.

My favorite water tests are hands down drop titrations. I find them the most accurate and while I’ve thought about it I have yet to splurge on a colorimeter. I’d love to figure out how to use my spectrophotometer as a pool colorimeter but I can’t find the exact math/procedures (if anyone has any tips I’d be pleased to hear them).

Taylor makes a boron drop test kit, but I do not believe or at least am not confident enough that it would accurately measure borate concentration. Has anyone used it?

Are my options really only between strips and a colorimeter?

Thanks
Click to expand...
ajw22 said:
A mannitol test for borates has been developed by some creative members. It is a bit complex and you can read about it here.

A commercial Borate Alkalinity Test Kit is available. This kit is similar to the TFP mannitol test process but keep in mind that the manufacturer has designed their test around industrial/consumer water sources that DO NOT contain a strong oxidizer like chlorine. So you may have problems with their test method if you don’t first neutralize the chlorine in your sample water.

Borates in pool - Further Reading

www.troublefreepool.com www.troublefreepool.com
Click to expand...
ajw22 said:
A mannitol test for borates has been developed by some creative members. It is a bit complex and you can read about it here.

A commercial Borate Alkalinity Test Kit is available. This kit is similar to the TFP mannitol test process but keep in mind that the manufacturer has designed their test around industrial/consumer water sources that DO NOT contain a strong oxidizer like chlorine. So you may have problems with their test method if you don’t first neutralize the chlorine in your sample water.

Borates in pool - Further Reading

www.troublefreepool.com www.troublefreepool.com
Click to expand...
Very interesting. I had read about the mannitol-borate complex but wasn’t sure if anyone had actually figured it out. I would order the borate alkalinity test you mentioned but I have to try to get an industrial proxy as I doubt they’d ship it to me.

Unrelated to the thread subject but I don’t want to post twice in quick sucession. You wouldn’t happen to have any insight on my spectrophotometer situation?
 
ThatOneExcelGuy said:
Very interesting. I had read about the mannitol-borate complex but wasn’t sure if anyone had actually figured it out. I would order the borate alkalinity test you mentioned but I have to try to get an industrial proxy as I doubt they’d ship it to me.

Unrelated to the thread subject but I don’t want to post twice in quick sucession. You wouldn’t happen to have any insight on my spectrophotometer situation?
Click to expand...

Nope. Maybe @JoyfulNoise does.
 
You’d have to find a complexometric indicator dye for borates that is sensitive to concentration. Curcumin/rosocyanine is one such compound but I believe it has some stringent pH adjustments that need to be made so that the yellow/red color properly develops and it would definitely need a chlorine neutralizer. You’d have to make several stock solutions with known boron concentrations and do a Beer’s Law plot to determine the molar extinction coefficient. The test may not work at standard pool concentrations of boron, so you might need to do significant dilutions of the test sample so that the color intensity is in the right range.
 
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You can get boron kits for spectrophotometers but other than chlorine the problem is the range and cost. Most kits are designed with a range that is too low for pool testing. Hach have a boron kit at ~US$500 with a range of 2 - 50mg/L which is still too low. Their other kits are even lower at 0.05 - 14mg/L. These kits are designed for their bench top meters that start at US$8500.00. I’m afraid it’s the mannitol test or guess strips.
 
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JoyfulNoise said:
You’d have to find a complexometric indicator dye for borates that is sensitive to concentration. Curcumin/rosocyanine is one such compound but I believe it has some stringent pH adjustments that need to be made so that the yellow/red color properly develops and it would definitely need a chlorine neutralizer. You’d have to make several stock solutions with known boron concentrations and do a Beer’s Law plot to determine the molar extinction coefficient. The test may not work at standard pool concentrations of boron, so you might need to do significant dilutions of the test sample so that the color intensity is in the right range.
Click to expand...
Thank you. I had figured I’d have to do something like this but I couldn’t figure out a suitable indicator dye. I’ve heard people kvetch about using rosocyanine. I’ll look in the literature and see if I can find anything. You’re probably right about having to dilute down. I’m in the somewhat odd position where I have a spectrophometer that was in no way designed for pool use. I had used it for SEC.
 
AUSpool said:
You can get boron kits for spectrophotometers but other than chlorine the problem is the range and cost. Most kits are designed with a range that is too low for pool testing. Hach have a boron kit at ~US$500 with a range of 2 - 50mg/L which is still too low. Their other kits are even lower at 0.05 - 14mg/L. These kits are designed for their bench top meters that start at US$8500.00. I’m afraid it’s the mannitol test or guess strips.
Click to expand...
I had worried this was the case. I’ll probably work with the test strips and see if I can work out a spectrophotometric method. Thanks.
 
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