Importance of TA in SWG pool with automatic acid dosing

Welcome to TFP.

As long as your TA stays above 50 don’t worry about your TA. Accept whatever TA your water chemistry reaches equilibrium at. TA does nothing for you except stabilizes your pH. And if your pH is stable then your TA is good.

What is your current pH and TA and what test kit are you using to measure it?

NathanScrivener said:

Hi all

We have just had a new fibreglass SWG pool installed and I am coming to grips with water chemistry.

The standard recommendation appears to be to keep TA in the 60-80ppm range. We have a ph sensor and an automatic acid doser. It seems that adding TA will likely cause more upward PH drift and the swings in ph you might ordinarily get with low TA would be controlled by the acid doser. So I am thinking adding TA in this instance is not necessary or ideal. However I am not sure about this so wonder what the consensus on here is?

Thanks in advance for any thoughts.

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I'm using acid dispensing via intellichem (uses pH probe to monitor) with very small dose amounts of 14.5% MA. My fill water is about 110ppm TA. I keep my ph between 7.3 (when water is warm 85+F) and 7.6 (when water is cold - 58F) to balance CSI (I have very high CA at 1100 right now).

My TA will be driven down to 40 by the frequent small acid doses the system does. I don't worry about it because the fill water is high in TA and so the bias in the pool as water is added is upward. I know this is below TFP recommendations BUT if I bring TA up it just causes the system to use a ton of acid to maintain the pH and the TA will drop gain to 40. So through a few years ow of experimentation - I leave the system stabilize where it wants. I've never had a pH crash, probably because of the MA microsdosing.

NathanScrivener said:

Hi all

We have just had a new fibreglass SWG pool installed and I am coming to grips with water chemistry.

The standard recommendation appears to be to keep TA in the 60-80ppm range. We have a ph sensor and an automatic acid doser. It seems that adding TA will likely cause more upward PH drift and the swings in ph you might ordinarily get with low TA would be controlled by the acid doser. So I am thinking adding TA in this instance is not necessary or ideal. However I am not sure about this so wonder what the consensus on here is?

Thanks in advance for any thoughts.

Click to expand...

Welcome to TFP!

What is the CH of your pool and fill water, and do you have a plaster pool? I assume that you get decent amounts of rain over winter, and your CH doesn't keep rising? Just make sure that you don't dial in a combination of low pH and TA, which would together with low CH result in corrosive water for plaster pools.

Use PoolMath and turn on CSI tracking and temperature tracking. Target a CSI (calcite saturation index) between -0.3 and 0 to prevent scaling of your pool surfaces and inside your SWG cell.

In many hot regions of the US, like Arizona, pool owners are usually dealing with high CH fill water and lots of evaporation which results in CH accumulation over time. Replacing evaporation losses with high CH fill water results in rising CH levels, because calcium doesn't evaporate with the water. Situation on the Australian east coast is different, and I assume also in New Zealand.

Do you have a decent test kit? The TFP method relies on precise home testing, no test strips or pool store testing.

Clear Choice Labs test kits are equivalent to the Taylor K2006-C that is recommended here, and they ship from Australia to New Zealand.

Going through the Pool Care Basics will give you an introduction to the TFP method.

mgtfp said:

do you have a plaster pool?

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NathanScrivener said:

We have just had a new fibreglass SWG pool installed...

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Dah, missed that. Thanks.