Low TC, high TA, High pH in hot tub-how to fix?

[Maggie]

Thanks for your response, waterbear. Our hot tub is acrylic, about 3 years old; we use bromine floaters instead of chlorine. Yes, we are using strips...just bought some new AquaCheck strips, in fact from the spa place (different brand, we had been using HTH) - we will get the Taylor strips you recommend. The spa is about 300 gallons. Using our test strips we got the following readings, done 3X to make sure (including once on our well water, which we use to fill):
Total hardness: zero (I assume this is TC, correct?)
Total bromine: zero (because we haven't put any in yet; our last water test of the tub water before filling it was 'very high' (>20)
Total alkalinity: high (240)
pH: high (> 8.4)

When the spa guys tested our old tubwater, he said it was basically battery acid because of the high bromine content - I wasn't getting why we would get such a high bromine content yet the pH is also way high, which to me indicates it's highly basic, not acidic. Your explanation of the high alkalinity leading to high pH makes sense. And you are the second person to say the very low calcium is nothing to worry about in a hot tub. So I guess we just need to lower the alkalinity at this point, which should lower the pH, and then add in however much bromine we need to bring it up to the ideal level of ~5 or so. I will consult the forum for how best to lower the TA. Thanks again for your quick response!

[waterbear]

Maggie, you don't want to be testing with strips. Period! They are worthless! As far as it goes the HTH strips are among the better ones since they are rebranded Taylor strips but no strip can give you the precision and accuracy and ease of reading as a GOOD test kit and for bromine it is the K-2106! You will probably have to order it on the internet. Amato industries seems to have the best price for this kit. If you are running a bromine tub then you want to get a Taylor K-2106 test kit which will test for total bromine, pH with acid and base demand tests, Total Alkalinity and Calcium hardness. This si what you need to test in a bromine tub. Also I suspect that you need soem guidance in how to properly maintain your tub water so I am referring you to a thread on a different forum that has more info on hot tubs (and where I am one of the moderators) where you will find the info you are looking for!:
Bromine for Beginners
How to lower TA (along with an explanation of what TA is and why it causes pH to rise)

Also, adding calcium has NO effect on the total alkalinity or pH of the water since it is added in the form of a neutral salt (calcium chloride).
If your spa guy said your water was basically battery acid because of the bromine content then it's time to ditch the spa guy. He doesn't have a clue! Your pH is high BECAUSE your TA is high. Period. It is cause and effect! High TA and aeration = pH rise. Period. It's really not rocket science but many in the industry cannot grasp this simple fact.

====================================

Also, the test for total chlorine and total bromine on the strips is the same test so if you have no bromine in the tub then the chlorine is going to register 0 also However, you really don't want to pay attention to any chlorine numbers since you are suing bromine. The tests are the same. The only difference is that to get a bromine reading the chloirne reading is doubled (actually multiplied by 2.25 but doubling is close enough for government work!)

[PoolDoc]

Membership updated.