Unusual test results

[ekapigian]

This is a new one for me so I could use a little guidance here. I recently drained and filled our spa and have been trying to get the water in balance but I'm getting unusual ph readings from my test kits. The oto tests are reading around 8.0-8.2, yet I'm getting readings of around 7.2-7.5 on my test strips. I've used three different test strips and 2 different oto tests, one is from my tf 100 kit. All tests were performed within 5 min window, and all test materials used aged from 1 yr to a few months old. My normal inclination would be to trust the oto kit but based on my experience owning the spa for the last 6 years, the test strips would be more in line with what I would expect it to be. Other readings are as follows:

Bromine - 5-7ppm (just shocked yesterday)
Ta - 60
Ch - 150
Ph - ??

Any ideas on what the heck is going on?

 

[kimkats]

How old is your TF-100 kit? How/where do you store it? Heat/cold/sun?

Kim

 

[duraleigh]

Use what you are calling "OTO". The test strips are likely the worst form of testing do not trust them. That pH test is called a phenol red test and is pretty standard for the industry. Unless you have left your reagent in the sun or outside for any real length of time, it is very dependable.

(The other half of the comparator block is yellow drops for chlorine test and that's the OTO test.)

 

[ekapigian]

Thanks for the reply. Yes that is the test I'm referring to, with the phenol red dye. The tf kit and all other testers are kept indoors out of the sun. It is only 1-2 mos old

 

[pooldv]

Stop using test strips and adding to your confusion. If you really want to compare the test strips to something then dip your finger in the water, hold it up to the wind and say the first number that pops in to your head. Test strips are completely useless. Taylor drop tests are the best in the industry.

 

[kimkats]

The "guess strips" are not worth the time to pull the water from the water. Use and trust your other test.

Kim

 

[pooldv]

Post a set of TF100 test results and we'll be glad to help.

Are the test strips in the trash yet?

 

[ekapigian]

The test results above are from the tf100. I have three containers of leftover test strips that I occasionally use just for quick check of levels. They are never totally accurate but always very close for measuring ph and TA. This is the first time I've seen such a wide margin amongst drop test and strips, especially when 3 different test strips all registered the exact same. I get it though...I'll trust the Taylor test.

 

[pooldv]

Ok, so hot tub maintained with bromine. Have you seen this handy bromine article for hot tubs?
How do I use Bromine in my spa (or pool)?

And add some acid to lower your PH to mid-7s.

 

[ekapigian]

Thanks. I have read that article. Very useful information.