Can someone tell me if an iron test kit will accurately measure iron ppm when a metal sequestering agent is used in the pool or will it not show the true iron level in the pool?
Thanks
Dennis
Thanks
Dennis
Iron Levels
- Thread starter dtarantino
- Start date
- May 23, 2015
- 25,799
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Typically that type of test requires a reducing agent step to destroy the sequestering agent and "free" the iron. You want a test that measures TOTAL iron. The problem is, most commercially available kits use an indicator dye method (tripyridyl-s-triazine) that is not compatible with high levels of polyphosphonates, i.e., the most common metal sequestering agent. PalinTest has some chemistries that can work when polyphosphonates are present, but they are typically based on an optical photometer testing apparatus. See here -
Iron testing - which method to use? | Palintest
Iron testing - which method to use? | Palintest
Similarly, what about iron in a pool where the iron has precipitated to solid form. Will the iron test measure that portion of the iron that has precipitated?
- May 23, 2015
- 25,799
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
It wouldn't measure that either.
If one wanted to know the total iron content, you could the AA treatment of the pool and dissolve all the stains. Then you could measure that water sample since ascorbic acid isn't a particularly strong sequestering agent compared to the polyphosphonates.
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Hi Dennis..just realized I hadn't answered your question about this in your pm.
I use iron test strips not to tell me total iron content for the reason Matt outlined above, but to tell me how much is not sequestered
I also use them on source water. None of that helps you in terms of getting a sense of the total concentration.
While I haven't done this, I have an experiment in mind that might help you get that number. Eg. Fill a 5 gal bucket with pool water. Add enough chlorine to the test bucket for SLAM level to oxidize the Sequestrant/phosphonic acid. Add some crushed up vitamin C -- it will fight the chlorine, I'd add it until I zeroed out on FC then add a bit more just to make sure the iron is released. Now test the iron.
Again, this in an experiment, so if Matt or anyone can think of a reason it won't work, feel free to defer to their wisdom. Its still cold in these parts for me to set up an outdoor bucket test but if I get time next weekend I may do a test inside the dome
I use iron test strips not to tell me total iron content for the reason Matt outlined above, but to tell me how much is not sequestered
I also use them on source water. None of that helps you in terms of getting a sense of the total concentration.While I haven't done this, I have an experiment in mind that might help you get that number. Eg. Fill a 5 gal bucket with pool water. Add enough chlorine to the test bucket for SLAM level to oxidize the Sequestrant/phosphonic acid. Add some crushed up vitamin C -- it will fight the chlorine, I'd add it until I zeroed out on FC then add a bit more just to make sure the iron is released. Now test the iron.
Again, this in an experiment, so if Matt or anyone can think of a reason it won't work, feel free to defer to their wisdom. Its still cold in these parts for me to set up an outdoor bucket test but if I get time next weekend I may do a test inside the dome
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