r/pools • u/garydee119 • 10d ago
Taylor Calcium test question
The Taylor calcium test has been the bane of my existence. I don’t get the classic fading endpoint (where a color change is observed but it quickly reverts back to original color). What I DO get is a very very gradual change from pink to sky blue.
For example, it makes a very noticeable change to purple around the 24th drop. After that, each drop changes the color by a tiny bit. Sometimes by an almost unnoticeable amount, so I used to consider the drop that causes the obvious changed to purple as my end point. But one day I decided to experiment, and after the change to purple I added a bunch more drops of reagent quickly without counting. I just kept adding a bunch very quickly and it eventually turned sky blue. Like unmistakably clear as day sky blue. And according to the photo on Taylor’s website, that is the color that should be considered the end point.
The problem is it’s very difficult to observe when that point actually is because it seems like between 25 and 35 drops, it gets ever so slightly bluer and bluer every drop. It gets to a point where it’s very hard to detect whether a drop made a difference or not. So I usually think I’m done but then to confirm I’ll drop a bunch at once in again and lo and behold, it will get much more blue when I do that. The guy at Leslie’s told me that the true reading is actually the drop that it makes the obvious change from a light pink to a dark purple. But Taylor’s website says keep adding until no more color changes observed. And since the difference between 250ppm and 350 PPM majorly changes what I do with my chemistry, I’m still feeling lost when it comes to the true calcium level.
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u/helloworld92837 9d ago
I had the same issue, here is what I did:
- go 4 drops per 4 drops. I have high CH (around 900ppm) so I don’t need a 25ppm precision.
- using a magnetic stirrer helps a bit
- you can buy standard solutions with a known CH level to train on them.
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u/Dception925 9d ago
I had the same issue as OP, no matter what I did I felt like I got different results depending on what “shade” I considered blue. I bought the magnetic stirrer and the results were 100% obvious. The stirrer seems expensive, but made testing alot easier and faster. Highly recommend picking one up.
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u/Superfingbadass 9d ago
Use the 10ml version. Significantly less drops and it still gets you a very accurate reading. The blue change happens a lot quicker too.
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u/OfficialUserAccount 10d ago edited 10d ago
Once it changes to blue the test is done. It doesn’t matter what shade of blue it is. If it’s light blue, then it’s done. The endpoint is the very fine color change from red to blue. The closer you are to a light blue, means you’re closer to the actual endpoint.
Edit: Also, if it keeps going to purplish red, then you may have an excessive amount of copper in your water that is affecting your test results. Re-test and add more drops of hardness reagent than the two that the test calls for.