pH keeps rising - does new liner or new heater contribute to this?

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ionizer

ionizer

Gold Supporter
Jun 7, 2016
255
Marlboro, NJ
Hello. First my #s:

FC: 6
CC: 0
pH: 7.9-8.0
TA: 100
CH: 170
CYA: 50
Temp: 82-84 F

I keep adding Muriatic Acid to get my pH back to 7.6-7.7, but every few days it seems to keep creeping up to high 7s or after 4 days w/o muriatic acid, now it is at almost 8

Does a new liner in anyway contribute to a higher than usual pH?
Does a new heater contribute somehow to a higher than usual pH?

I've never really experienced a "continually rising" pH in the past and usually was in the 7.3-7.5 range fairly consistently.

Is my TA @ 100 vs say an 80 causing it?

Is it just a natural expectation with rain water and just need to accept it and pour muriatic acid in as needed?

What am I missing here?
 
Neither the liner nor the heater will contribute to pH rise. Your TA at 100ppm definitely will especially as the water gets warmer. Try using the acid/aeration process to bring your TA down to 80ppm and I bet you’ll find your pH stabilizes much better.

The presence of carbon dioxide/bicarbonate/carbonate (CO2/HCO3-/CO3--) alkalinity means that your water will always have a natural, equilibrium pH above 8.0. Therefore your pH will always want to rise. Lowering TA with acid and aeration reduces the carbonate alkalinity of the water and slows that process of pH rise significantly.
 
JoyfulNoise said:
Neither the liner nor the heater will contribute to pH rise. Your TA at 100ppm definitely will especially as the water gets warmer. Try using the acid/aeration process to bring your TA down to 80ppm and I bet you’ll find your pH stabilizes much better.

The presence of carbon dioxide/bicarbonate/carbonate (CO2/HCO3-/CO3--) alkalinity means that your water will always have a natural, equilibrium pH above 8.0. Therefore your pH will always want to rise. Lowering TA with acid and aeration reduces the carbonate alkalinity of the water and slows that process of pH rise significantly.
Click to expand...

arg, that's what i feared. Overdid the alkalinity earlier this year! Ugh! Thanks.
 
Higher water temperatures cause more pH rise. So, if you're heating the water, you will get more pH rise.

Think about a beer or soda going flat (losing carbon dioxide).

Warmer temperatures or agitation (aeration) increases carbon dioxide loss.

A certain percentage of the bicarbonate will convert to carbon dioxide depending on the pH.

pH........%CO2
7.2........ 11.2
7.3......... 9.1
7.4......... 7.4
7.5......... 5.9
7.6......... 4.8
7.7......... 3.8
7.8......... 3.0

So, the TA x the percentage determines how much carbon dioxide is in the water.

A lower pH causes more carbon dioxide and has higher pH rise.

For example, a TA of 120 and a pH of 7.4 will have about 4.9 times as much carbon dioxide as a TA of 60 and a pH of 7.8.

If the amount of carbon dioxide is low enough, it will be reach equilibrium with the carbon dioxide in the air and pH rise will stop.
 
JamesW said:
Higher water temperatures cause more pH rise. So, if you're heating the water, you will get more pH rise.

Think about a beer or soda going flat (losing carbon dioxide).

Warmer temperatures or agitation (aeration) increases carbon dioxide loss.

A certain percentage of the bicarbonate will convert to carbon dioxide depending on the pH.

pH........%CO2
7.2........ 11.2
7.3......... 9.1
7.4......... 7.4
7.5......... 5.9
7.6......... 4.8
7.7......... 3.8
7.8......... 3.0

So, the TA x the percentage determines how much carbon dioxide is in the water.

A lower pH causes more carbon dioxide and has higher pH rise.

For example, a TA of 120 and a pH of 7.4 will have about 4.9 times as much carbon dioxide as a TA of 60 and a pH of 7.8.

If the amount of carbon dioxide is low enough, it will be reach equilibrium with the carbon dioxide in the air and pH rise will stop.
Click to expand...

when you say "heating the water" does this pertain to the act of using the heater or is it in general "the water being heated" naturally by the sun or simply more explicitly, just referencing the water temperature itself. i.e. 90F will have what you describe more so than 70F degree water.
 
Warmer water causes faster pH rise. Heating has a small effect due to the water temperature in the heat exchanger.

However, in general, it's mostly the water temperature.
 
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