Pocket PH tester

[LITTLEJJ]

I hate using the drop test for PH. Leslies has a pocket PH tester for about 45.00. Has anyone used this? If so, how accurate is it? Also, can it be adjusted? I can get buffer solution from work if it is adjustable.

[fcfrey]

I've used a dozen different electronic tester ($20.00 to $300.00) and have returned or trashed them all. First of all you get what you pay for. Those that cost a lot are accurate but need to be calibrated with a buffer solution of a known pH value (usually 4.01 & 7.00). If the device doesn't require calibration I'd be very skeptical of the results.

The drop test is best unless you have difficulty differentiating colors, then the electronic testers may be the best for you.

If you search this site there have been lots of opinions offered. Seems like most are negative.

[caustik]

I am in the same boat as you, I can't with great certainty tell what the PH is with the drop kit. I am ordering the tester in the link below in the spring. It does need calibration but I don't have a problem with that. Someone here or on another pool forum recommended it.

http://www.coleparmer.com/catalog/product_view.asp?sku=3563430&pfx=EW

[giroup01]

I agree with frfrey here, I think they're more of a hassle than anything else, you have to get the calibration solution, make sure they're not expired, calibrate the thing properly (I used to do a 4-7-10 calibration). Also the level of precision is not _that_ important, I mean, if it's 7.24 or 7.21 it doesn't matter.

If you're getting a probe I do recommend one with a temperature probe, or one with temperature compensation, as pH is a function of temperature.

And make sure the sensor is replaceable.

[LITTLEJJ]

Yea, I kinda thought a cheap PH meter would be cheap. But I was hoping people here would say it was OK. Like was posted before, you get what you pay for. I guess I will keep trying to read between the colors. Thanks for the responses.

[waterbear]

Y I guess I will keep trying to read between the colors.
reading phenol red reagent for pH is easy. You really don't even need to look the comparator once you learn the colors!

Here are ballpark colors that will get you in the right place:
red to purple-- pH is high (above 7.6)
orange to red-- ph is OK (7.4-7.6)
ORANGE pH is 7.4
yellow to orange-- pH is low (below 7.4)
(the red is a pinkish red, btw)

That is really all the precision you need for your daily pH test, IMHO.
It's not rocket science. Don't make it harder than it needs to be. If you shoot for orange you pH will be within range, perhaps a bit low for some but still acceptable)
(Now I await all the bashing with baited breath! ;))

Now, if you are trying to fix a problem (such as lowering alkalinity) then it is possible that you might need more precision, but if you are just checking to see if things are ok or even making small adjustments to pH that is really all the precision you need.

IMHO, pH meters are NOT worth the time and trouble. I have used them in laboratory settings (expensive ones with a lot pf precision) and they require constant calibration (calibartion solutions are expen$ive) for accurate results. Also the probes are delicate and need to be replaced on a regular basis ($$$). They are really not going to save you any money or time over using a drop based kit. In reality they could take more time to use and end up costing more!

[Poolsean]

No bashing here.
I know most of the pool industry professionals can support this statement;

"some" pool service companies are very familiar with what Waterbear describes and rather than doing an actual pH test, they drop the reagent directly into the pool water and see what color it turns to.

Test blocks? We don't need no steenkin' test blocks.

Although not generally accepted as a legitmate test, it's close enough.
BTW, they also do this with OTO reagent for chlorine testing...NOT A GOOD IDEA, since we know how important is it to verify the combined chlorine levels too.

[jman311]

I think I might fall under the "slightly colorblind" or maybe a better term would be "color indecisive" category, as I always think my pH test color can be described as "reddish" at best and I am never satisfied with it's accuracy. So, I have also been considering trying a pH meter instead of drops so have been doing a little research...

A few things I have read:

Temperature compensation is not important in testing pool water, as it is basically irrelevant at pH levels near 7. Only when pH is considerably higher or lower (< 4 or > 10) will temperature significantly alter the reading.

pH meters do need to be calibrated, but I read one opinion that once a month should be enough. I haven't been able to determine how far off your "average" meter will become after a given amount of time, but I wonder would it really be enough to signifcantly alter the reading? Say if even if it was off by +/-0.1 after a month's time, if you are like me that's probably still more accurate than reading a drop test.

I suppose with the need for calibration solution it is likely more expensive overall to use a digital ph meter, but if calibrating once a month is sufficient, I think the convenience and confidence of a more accurate reading might be a worthy trade-off. One particular dealer sells 475ml of calibration for $5 and claims a 1-year shelf life. I figure calibrating using solutions of 7 and 10 ought to be good enough for pool purposes, so that's only $10 a year.

Can anyone comment on the frequency of calibrations? I wonder how often is really necessary and how inaccurate meters become as a function of time.

I welcome discussion and any further insight...

[CarlD]

I think I'll get my little one to help Evan with his colors. He's 2 and if you ask him what ANY color is, he says "Orange!" (including the exclamation point).:p

Evan, then you will NEVER have problems with pH!:D

[waterbear]

I think I'll get my little one to help Evan with his colors. He's 2 and if you ask him what ANY color is, he says "Orange!" (including the exclamation point).:p

Evan, then you will NEVER have problems with pH!:D
Carl, have him test YOUR pool. It will be perfect all the time!:D