water temperature and ph testing

[Guest Guest_Tony_*]

I have a Spa which is hot all the time. I am told that many of the routinue tests (ph, total alkalinity) are not accurate at 104 degrees and should be tested cooler. Is this true? If so, how does one do this with a spa that never cools off? Do I collect a sample and let it cool, then run the tests? Advice please, and thanks in advance!!

[Guest Pete]

Yes, let it cool down. It can't hurt and high temp may interfere with the reagents.

[Guest Sally]

104 is the MAXIMUM temp for a spa. It's really not good for YOU or the spa to keep it that hot all the time. I agree with Pete, let it cool down, then take the tests.

[Guest Scott]

Doesn't make sense. Spas are hot and need to be tested as such.

Who is it that told you the tests aren't accurate at 104 degrees? What do they expect you to do? How reliable is/are they? That's what you need to look at. I've seen nothing in any of the testing material related to only testing cool.

Sorry Pete and Sally, but your answers have no basis in fact - only opinion ("it can't hurt" isn't a reason to test at a cooler temp. And 104 isn't a problem for the spa - that used to be the norm for therapy. People want cooler temperatures now because spas have become more social and cool temps let them stay in longer.

[bendite]

I contacted Taylor Technologies and they confirmed that before testing water samples you should let the sample Cool off first. Hot water does affect the reagents. I did not get a allowable temperature however.

This does not mean lowering your spa temp, just the sample.

Surprisingly Taylor test booklet suggest's testing the sample immediately, I am guessing this is a "pool" suggestion since the pool water is colder.

Anyone know if room temperature would be OK?

[chem geek]

Most chemical tests for pools and spas are designed and calibrated for room temperature near 25C which is 77F (so a "warm" room). Though Taylor is correct that it is best to perform most tests at this temperature (anything from 70 to 85 should be OK), some tests are more affected by temperature than others. The most affected are solubility tests such as measuring the turbidity in the Cyanuric Acid (CYA) test. Since most pool water is in the 82-88 range, this is close enough to room temperature so is why they say you can test right away -- mostly so that water chemistry parameters don't change from outgassing of chlorine, etc. The pH of water actually changes a little with temperature. With a TA of 100, water at 85F with a pH of 7.5 will have a lower pH of 7.4 at 104F.

It might be interesting for you to try measuring both ways -- near the 104F temp immediately after taking a water sample from the spa and testing again but after the letting the sample sit at room temperature for a while (but keep the sample tube covered to minimize any change in water chemistry parameters). If you do this, let us know what you find out. I suspect that there won't be that much difference in the tests, except for the CYA test.

Richard

[bendite]

here is a response from Taylor Technologies when I asked why their literature said test immediately but their customer service said let samples cool off.

Dear Bendite,

Thank you for your email, it was forwarded for my reply. Higher spa temperatures can affect test results. The current recommendation is to let spa water cool to an ambient temperature or at least under 90ºF before testing. If you take a 25 ml sample of the hot water and let it sit for about 30 seconds, which could still be considered immediate. It usually cools down enough to get an accurate test.

Sincerely,

Jarad Proctor

Customer Service, Technical Support

Taylor Technologies, Inc.

800-TEST KIT (837-8548)

(F)410-771-4291