Ph question.

[mgtfp]

As revitup said. I also do other tests while waiting for the meter to stabilise. The smiley usually appears pretty quickly, but I leave it a bit longer usually.

If you just want a quick "yes, my pH is the 7s", then about 30sec is probably enough. If you want to be a bit more nerdy about it (aren't we all a bit nerdy round here?), Then you can wait a bit longer.

The important bit (to really make use of the two digits of the pH60 and not just get fooled that you have a very precise measurement) is to make sure that the temperature that the meter shows is sufficiently close to the actual water temperature, otherwise the meter will use the wrong temperature for the automatic temperature compensation.

In summer that thermalization is pretty quick. In winter, when putting a room temperature meter into near freezing water, it can take a bit longer. I usually wait until the meter's temperature is within 2°C of the water temperature, that gives me very reproducible readings. When the water is very cold, the water sample should be sufficiently large, so that the meter actually cools down to the water temperature and not the other way round.

 

[revitup]

The important bit (to really make use of the two digits of the pH60 and not just get fooled that you have a very precise measurement) is to make sure that the temperature that the meter shows is sufficiently close to the actual water temperature, otherwise the meter will use the wrong temperature for the automatic temperature compensation.

When you say “actual water temperature “ you’re referring to the sample, correct? Not the pool temp? You want the temp indicated on the meter to accurately reflect the sample temp?

 

[pb4uswim]

I got a cheap PH meter off of Amazon. Given that PH is not critical to have a precise measurement, I think it’s fine. I calibrated it when I bought it and it works fine. I also use the drops (R-0014) with the basic test kit and it seems to confirm the meter very well. For example, if my meter reads 7.6 I look at the drops readout and if it looks to be below 7.8, I’ll call it good. My understanding is that PH just needs to be in the 7’s so I don’t see the point of spending too much money to try to be exact.

 

[revitup]

I got a cheap PH meter off of Amazon. Given that PH is not critical to have a precise measurement, I think it’s fine. I calibrated it when I bought it and it works fine. I also use the drops (R-0014) with the basic test kit and it seems to confirm the meter very well. For example, if my meter reads 7.6 I look at the drops readout and if it looks to be below 7.8, I’ll call it good. My understanding is that PH just needs to be in the 7’s so I don’t see the point of spending too much money to try to be exact.

I agree except if you’re interested in keeping track of CSI. PH in the low 7s vs high 7s has a pretty significant effect on calculated CSI in Poolmath.

 

[Snoobug]

I put the apera directly in the pool and got an immediate smiley!

 

[mgtfp]

When you say “actual water temperature “ you’re referring to the sample, correct? Not the pool temp? You want the temp indicated on the meter to accurately reflect the sample temp?

Your sample temperature should reflect the pool water temperature. If you take a sample from near freezing pool water and let it warm up to room temperature before testing for pH, then you will get the pH for water at room temperature and not the pH as it currently is in the pool.

 

[revitup]

Your sample temperature should reflect the pool water temperature. If you take a sample from near freezing pool water and let it warm up to room temperature before testing for pH, then you will get the pH for water at room temperature and not the pH as it currently is in the pool.

If I take a 90 degree water sample out of the pool and into the house to test it isn’t going to stay 90 degrees long. If I’m going to get a different reading depending on the sample temp, that doesn’t sound like it’s temp compensated to me. Seems like the opposite. Sounds like temperature dependent. Confusing terminology. No wonder the reading drifts as it sits there on the bench.

 

[Snoobug]

If I take a 90 degree water sample out of the pool and into the house to test it isn’t going to stay 90 degrees long. If I’m going to get a different reading depending on the sample temp, that doesn’t sound like it’s temp compensated to me. Seems like the opposite. Sounds like temperature dependent. Confusing terminology. No wonder the reading drifts as it sits there on the bench.

The bouncing makes sense. How does temperature impact Ph? Taking a 90 degree sample into a 74 degree house... decreases or increases Ph?

 

[Panzer]

If your pH probe is taking a lot longer to stabilize (smiley face is blinking a bit) than it used to, it may help to use some of the 3M KCL solution and soak your probe in it.
As probes age they can take a bit longer to stabilize and eventually, will need replacing. A nice aspect of the Apera pH 60 is the probe is replaceable.

Don't forget to recalibrate and/or verify your probe against a known buffer frequently.
Respectfully,

Edit- Here's a link to Apera's FAQ on whether or not your meter is accurate.

 

[mgtfp]

The bouncing makes sense. How does temperature impact Ph? Taking a 90 degree sample into a 74 degree house... decreases or increases Ph?

pH rises when water cools down, real effect, has nothing to do with any temperature compensation. When you now take the sample inside and let it warm up, then the pH will get lower. That can make you think that the pH is lower than it actually is. I have seen a pH difference of about 0.2 when letting a cold sample warm up.

Bringing a warm sample into an a/c environment will have the opposite effect, but probably less than 0.2 as the temperature difference is usually not as big.

When the difference between pool and house is big, then I usually dip the meter straight into the pool or bring a larger sample (like ice cream tub) inside.

The other effect is temperature difference between meter and sample, which will make the meter think that the water is at the meter's temperature when it's actually not, and will confuse the temperature compensation algorithm. So even when you put the meter straight into the pool, the pH will drift for a while until the meter has thermalized to the pool temperature (the pool water temperature will stay constant). When you have a permanent thermometer in the pool, you will see that the temperature displayed at the meter will slowly drift towards the water temperature and that pH will also drift until the temperature drift slows down.

That second effect is usually small, unless you are dealing with very cold winter water, and can usually be ignored for standard "yes, my pH is OK" testing. But it is noticeable.

When meter and water have the same temperature (and the temperature doesn't change), the measurement stabilises very quickly and doesn't drift.

 

[Snoobug]

pH rises when water cools down, real effect, has nothing to do with any temperature compensation. When you now take the sample inside and let it warm up, then the pH will get lower. That can make you think that the pH is lower than it actually is. I have seen a pH difference of about 0.2 when letting a cold sample warm up.

Bringing a warm sample into an a/c environment will have the opposite effect, but probably less than 0.2 as the temperature difference is usually not as big.

When the difference between pool and house is big, then I usually dip the meter straight into the pool or bring a larger sample (like ice cream tub) inside.

The other effect is temperature difference between meter and sample, which will make the meter think that the water is at the meter's temperature when it's actually not, and will confuse the temperature compensation algorithm. So even when you put the meter straight into the pool, the pH will drift for a while until the meter has thermalized to the pool temperature (the pool water temperature will stay constant). When you have a permanent thermometer in the pool, you will see that the temperature displayed at the meter will slowly drift towards the water temperature and that pH will also drift until the temperature drift slows down.

That second effect is usually small, unless you are dealing with very cold winter water, and can usually be ignored for standard "yes, my pH is OK" testing. But it is noticeable.

When meter and water have the same temperature (and the temperature doesn't change), the measurement stabilises very quickly and doesn't drift.

This is great info thank you! I have had the most stable and quickest results sticking it right into the pool.