TA test is red

[sehaasch]

I tried testing the TA in my spa using the Taylor K-2006. I added 2 drops of R-0007 with no color change. But when I added 5 drops of R-0008, it turned red instead of green. When I tested my pH, it was extremely low (don't know if that info helps). What gives? These past two days there were 2 bathers using the spa separately for 30 minutes at a time.


260 gal., outdoor, bromine, cylinder filter

 

[duraleigh]

On many of the color change tests, it is surprisingly not important what the colors are.
What matters is the point at which the color changes. How much R-0009 did you use to change the color?

 

[sehaasch]

I stopped counting after 50 drops with a 25ml sample. Then I used a 10ml sample and stopped counting at 40. It never changed color.

 

[JasonLion]

If the sample turns red as soon as you add R-0008, your TA is zero and your PH is very very low.

PH that low can damage the pool surface and equipment, I recommend you raise the PH into the normal range as soon as possible. In a spa, you can raise the PH by raising TA to around 40 or 50 and then running the spa jets until the PH comes up to where you want it.

 

[sehaasch]

Before I saw your reply, I used pH-Up and brought the pH up to 7.4. I re-tested the TA and now it turns green and the reading is 50. Should I raise the pH any higher?



260 gal., outdoor, bromine, cartridge filter

 

[JasonLion]

That is fine for now. You can fine tune it as needed later.

 

[sehaasch]

When I'm doing the various tests, is it okay to use a large container to scoop out the spa water and then pour it into the test kit container (so I don't have to go outside in fridged temps more than once). Does anything change chemically if the water sits for 10-15 minutes while I'm testing?

 

[JasonLion]

It is fine to use a container for the spa water and do the tests indoors so long as your do the PH and FC/CC/TC tests first thing on coming inside. PH and chlorine levels can change fairly quickly, say in 15 minutes to an hour, simply because the water is removed from the pool. By testing them first you avoid that issue. None of the other tests really care about timing.

 

[chem geek]

When the TA turns red immediately after adding the R-0008 dye, that means that you not only have zero TA but that your pH is around 4.5 which is quite low. Good thing you caught this quickly and adjusted the pH and TA up.

As for how the TA could have dropped so far, you probably were using some net acidic chemicals such as Dichlor or non-chlorine shock (MPS) or bromine tabs. They would all lower the TA over time.

 

[Richard320]

When I'm doing the various tests, is it okay to use a large container to scoop out the spa water and then pour it into the test kit container (so I don't have to go outside in fridged temps more than once). Does anything change chemically if the water sits for 10-15 minutes while I'm testing?

Carrying the sample off somewhere is actually the norm around here. Also, if you get yourself a piece of 1/2" PVC pipe, you can use it as a pipette to draw the water out from a couple feet down within plunging your arm in the frigid water. Just cap it with your thumb, plunge it in, release your thumb, and it fills. Cap it again, swing it out and release it into your sample cup. Done. Check pH and FC first. CYA will need to warm up some before testing, but that's not needed more than about once a month normally.