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Ask Machinc Your Own Question
Machinc, General Contractor
Category: Pool and Spa
Satisfied Customers: 920
Experience:  Has written home improvement articles since 2008. Earned South Carolina Residential Builders License in 1991.
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I have a problem on TA. It reads low means 0ppm, pH on border

Customer Question

I have a problem on TA. It reads low means 0ppm, pH on border 7.7. FCL and TCL are fine 3.0ppm, Calcium Hardness 200ppm. For the last 14 days I have put in Sodium Bicarbonate for 8 kgs total (about 3 or 4 days on single treatment) and the TA is only read 6 ppm somehow the pH is now increase to 7.9. Water remain sparkling blue. My question is which should be adjusted first? PH or TA? Today, i decided to put in liquid acid and the ph down to 7.5 and the TA read back to low. What caused TA is hardly increased? For information, swimming pool, Gunite, 75,000 litres, sanitized by chlorine. Water tested by Lamotte colorQ test tabs pro 9. I have turn off any return jets so there is no aeration in the pool.
Submitted: 2 years ago.
Category: Pool and Spa
Expert:  Machinc replied 2 years ago.
TA should be adjusted first.'
Total alkalinity affects and changes the PH.
the higher the TA the more stabke the PH
more people can use trhe pool
Without affectingvthe PH
About 80/120 Ppm Customer
Expert:  Machinc replied 2 years ago.
The pool can show acceptable PH
with low TA
. The adding of chemicals ;
can change the Ph however with low TA
these numbers will not remain stable.
Expert:  Machinc replied 2 years ago.
You should maintain a PH
Level of 7.2 -7.8
Too low means more acid
in your water deteriorates pump and heater parts.
Too high is not good either.
Causes cloudy water, calcium build up Customer
Customer: replied 2 years ago.
Since You suggest to adjust TA first, do you mean I just need to increase TA to about 80 ppm regardless it will also increase the pH to about 7.9 or 8 even more? Does Chlorine will be less effective on high pH? The trouble start when I want to keep the pH below 7.8 for chlorine effectiveness while increase TA to about 80-120ppm ideally. My question is why the pool water TA is hardly to increase even I have put in 8kgs of sodium bicarbonate and still reading 6 ppm? Are there factors that prevent TA to increase?
Customer: replied 2 years ago.
So my question is how to keep the pH below 7.8 while low TA reading require me to add sodium bicarbonate and at the same time, it will also increase pH.
Customer: replied 2 years ago.
This the latest result just now:
pH: 7.7
TA: 4 ppm
Expert:  Machinc replied 2 years ago.
You have to raise the TA so I like and small status
Expert:  Machinc replied 2 years ago.
Disregard the above box it saved before I could edit. You have to raise the TA level slowly and in stages
Until it reaches 80
It may take several hours but the pH will settle down to a normal level
Customer: replied 2 years ago.
i have put 8 kgs sodium bicarbonate already within this week and could only raise by 6 ppm, and in my opinion this is abnormal, 1 kg normally should raise TA by 10 ppm. Is there anything I missed that hardly to increase TA?
Expert:  Machinc replied 2 years ago.
You are using the right chemical to
Increase TA
basically baking soda
this should be mixed in a bucket
of water and added in small amounts.
The pump should be on.
One pound can take up to three
hours to take affect.
Do not add any other chemicals
during this time
i am going to post a link with some
helpful information. It goes into a lot of detail