Air conditioner effect on pH

[miggs76]

Last week when I had the air conditioner on in my house I saw a drop in pH. The next day was cool outside and the pH was back to normal. Yesterday I had the air on and I saw another drop in pH. So I'm thinking that the A/C is causing this. Other than opening some windows to let some fresh air in are there any remedies for this? The tank is in the basement which is a big plus when the temp outside gets near 100---it stays nice and cool down there and my tank temp never gets higher than 81.

[DaveS]

It probably isn't the AC. It's probably you closing the windows to keep the AC in. CO2 buildup during winter months when everything closed to retain heat in is fairly common. Sounds like you have the same thing but just for the AC instead.

[miggs76]

It probably isn't the AC. It's probably you closing the windows to keep the AC in. CO2 buildup during winter months when everything closed to retain heat in is fairly common. Sounds like you have the same thing but just for the AC instead.

 

It is kind of the opposite----we don't ever open the windows in our house. During the cooler spring days the pH is normal (around 8.2) It is just when the ac comes on that the drop happens and it goes down to 7.9 or so.

[Origami]

Interesting. Is this a central AC / heating system? If you just turned the central fan on, does it impact the pH in the tank? (I'm wondering if the turnover between the upper levels and the basement are affecting this.) Does the probe cable run anywhere near any electrical that's feeding the AC system?

[miggs76]

Interesting. Is this a central AC / heating system? If you just turned the central fan on, does it impact the pH in the tank? (I'm wondering if the turnover between the upper levels and the basement are affecting this.) Does the probe cable run anywhere near any electrical that's feeding the AC system?

 

It is central AC. I'm not sure about the fan. It gets very cold in the basement when the A/C comes on because it's naturally cool down there anyway. I'm going to do some more tests on it. As a last resort I can simply block the air duct that comes into the room I guess--it really doesn't need to be cooling that room anyway. The probe isn't near any electrical that is feeding the system.

[Origami]

It gets very cold in the basement when the A/C comes on because it's naturally cool down there anyway.

Is this on an Apex or some other device that has temperature compensation? One possibility is that the probe input circuit on the measuring device is varying with the room temperature and, if the temperature swings are pretty wide down in the basement, maybe this is causing the measurement swings. If this were the case, the pH in the tank is not actually swinging widely, but the measurement is. One way to check is to measure the pH of some calibration solution when the basement is really cold from the AC being on and at other times when it's warmer after having been off for a little while.

[miggs76]

Is this on an Apex or some other device that has temperature compensation? One possibility is that the probe input circuit on the measuring device is varying with the room temperature and, if the temperature swings are pretty wide down in the basement, maybe this is causing the measurement swings. If this were the case, the pH in the tank is not actually swinging widely, but the measurement is. One way to check is to measure the pH of some calibration solution when the basement is really cold from the AC being on and at other times when it's warmer after having been off for a little while.

 

That's a good idea. I'll try it. yes, it is an Apex. Does turning on the temperature compensation alleviate this?

[Origami]

 

That's a good idea. I'll try it. yes, it is an Apex. Does turning on the temperature compensation alleviate this?

Normally temperature compensation adjusts for the probe temperature, not for the input circuit. Normally this is not an issue because temperature is fairly constant overall.

 

(Sent from my phone)