Using a Digital pH Probe

[setsailsoon]

Folks,

I've been meaning to do this post with photos for a long time. May be helpful to those that have the color blind issue I do that makes it almost impossible to discern pH color shades above 7.6 or so. Also, helpful for those that want to know pH when FC is above 10. Digital probe pH readings are not affected by high FC level. Probably the biggest pain for the pen-type probes is calibrating the thing, I found a little container pictured below that really helps. I change the solution every one to two weeks. Every other time I use the probe I shake off any liquid then dunk it in calibration solution then shake off then dip it again a time or two. I've been using the Phep from Hanna and it is clearly better than some of the cheaper ones. There are several brands in this price range and I think they're all about the same. When I set out to do my pH, FC, CC I just do the probe dip and shake routine then let it sit in the container while i do the FC and CC. After that's done I check the pH. It almost always reads 7.0 dead on. Then I just dip it in the pool and swirl a little then press power and I have my pH reading. Once you get the hang of it and the right little container I don't think this takes even a minute longer than doing the drop test for pH. You do require the pH calibration solution so it's always going to be a tad more expensive. But it's not really that hard and nice to be able to measure pH at any FC level.

I hope this is helpful.

Chris

 

[Dirk]

OK, I gotta be fair because I tend to rag on pH probes (just-another-needless-gizmo type rhetoric). But you've explained two excellent reasons to use one. The color-challenge I have begrudgingly conceded to before, but being able to keep an eye on my pH during a SLAM is a second, most excellent reason. My first thought was to claim: "Well, with TFP I'll never have to SLAM!" but even I can't hang a hat on that one. Nice write up!

 

[Wobblerlorri]

but being able to keep an eye on my pH during a SLAM is a second, most excellent reason.

After reducing your pH to 7.2 pre-SLAM, you can't really get an accurate pH reading in the highly chlorinated water. Most of us just let pH slide during a SLAM, and it quickly normalized after the SLAM is done.

 

[an1vrsy]

How can you concentrate on your pH reading when your Cox cable remote is on the table? Doesn’t that mean, you’re watching TV? <smile>

 

[setsailsoon]

Comcast

 

[Dirk]

After reducing your pH to 7.2 pre-SLAM, you can't really get an accurate pH reading in the highly chlorinated water. Most of us just let pH slide during a SLAM, and it quickly normalized after the SLAM is done.

Chris is saying his probe can get an accurate pH reading in highly chlorinated water. If I had to SLAM for more than a week I'd be very anxious about the pH if I wasn't able to test it. My pool gobbles acid.

 

[HermanTX]

Folks,

I've been meaning to do this post with photos for a long time. May be helpful to those that have the color blind issue I do that makes it almost impossible to discern pH color shades above 7.6 or so. Also, helpful for those that want to know pH when FC is above 10. Digital probe pH readings are not affected by high FC level. Probably the biggest pain for the pen-type probes is calibrating the thing, I found a little container pictured below that really helps. I change the solution every one to two weeks. Every other time I use the probe I shake off any liquid then dunk it in calibration solution then shake off then dip it again a time or two. I've been using the Phep from Hanna and it is clearly better than some of the cheaper ones. There are several brands in this price range and I think they're all about the same. When I set out to do my pH, FC, CC I just do the probe dip and shake routine then let it sit in the container while i do the FC and CC. After that's done I check the pH. It almost always reads 7.0 dead on. Then I just dip it in the pool and swirl a little then press power and I have my pH reading. Once you get the hang of it and the right little container I don't think this takes even a minute longer than doing the drop test for pH. You do require the pH calibration solution so it's always going to be a tad more expensive. But it's not really that hard and nice to be able to measure pH at any FC level.

I hope this is helpful.

Chris
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Ok. You perked my interest. I searched pHep and found one reference by Hanna Instruments om Amazon for $125 that looks like your picture. It did not indicate it provided a calibration solution. Where do you obtain that? If you can provide any details to purchase the pH sensor or the calibration solution would be appreciated.

 

[setsailsoon]

There are two versions of this probe. One is accurate to .01 pH units and costs $100+. .01 pH unit accuracy is way more accurate than needed. The one I use is accurate to .1 pH units; it's about $40 at the Hanna site and another outlet (Salt Water Aquarium). It comes with two point calibration solution packets (7.01 and 4.01). I only use the 7.01 and do single point calibration which also seems to work fine. I did comparisons of this unit with the Taylor drop test and it was identical through the range (wife helped with this since I can't read the drop test reliably). You need to buy calibration solution separately. This is one of the disadvantages of a digital probe and costs under $15 for 500 ml. This lasts about 12 months if you calibrate the way I describe above. I preferred the Hanna because it has a renewable reference anode that you pull out when needed from a roll that's contained inside the probe housing.

There are several very cheap pen style that read .01 but my experience is they don't do this accurately very long. Within weeks they start to drift and if you accidentally dry the tip out they're toast. Now there are also several brands under $50 that all appear to have the same quality as the Hanna Phep and even one that has a replaceable probe ($15) for this price. Apera, Milwaukee, and Beverage Doctor are a few brands I've seen that may have competitive offerings.

Hope this helps.

Chris

 

[Katodude]

Ok. You perked my interest. I searched pHep and found one reference by Hanna Instruments om Amazon for $125 that looks like your picture. It did not indicate it provided a calibration solution. Where do you obtain that? If you can provide any details to purchase the pH sensor or the calibration solution would be appreciated.

You can buy calibration solution from Amazon. They sell a bunch of different brands. Also single point calibration is probably enough for a pool since you are not trying to measure anything higher that 9 or lower than 6.

 

[dschlic1]

I use the HM Digital PH-200. What is nice about this meter is that the probe is replaceable. I use Hach powder pillows for the calibration solutions.