Is there a way to test the pH without having to color match? I'm having a hard time being able to distinguish color changes. I have tried it in daylight, artificial light, different backgrounds, etc.
pH Testing Question
- Thread starter PoolStudent
- Start date
Nope. The Taylor is the best pH test kit.
The exact pH level does not really matter. If the sample is not pink and not yellow, you are usually fine. You could get a bottle of the acid demand reagent (R-0015) and use that to help you match colors.
For me I have learned that 1 drop of acid demand requires ~1/4 gallon of muriatic acid in my pool.
The exact pH level does not really matter. If the sample is not pink and not yellow, you are usually fine. You could get a bottle of the acid demand reagent (R-0015) and use that to help you match colors.
For me I have learned that 1 drop of acid demand requires ~1/4 gallon of muriatic acid in my pool.
I'm trying to keep my pH at 7.4 to 7.5 to keep staining to minimum, but I can't really tell much a difference between 7.2 and 7.5.
There would be less staining at lower pH .... so not sure it matters. Although keeping the pH too low could be bad for your plaster.
With the demand reagents it gets to be pretty easy to see colors that match.
With the demand reagents it gets to be pretty easy to see colors that match.
Well, if you had lots of money and you were diligent about cleaning and calibration, you could buy a high-end, 3-point calibration pH probe. They cost somewhere north of $800 and you'll have to factor in probe replacements about once every two years or so depending on how well you keep them....
Or, a cheaper way would be to use your acid demand reagent to see how the color changes with each drop and then count the number of drops it takes to get to the lowest pH color on the scale (yellow).
Perhaps @chemgeek could give us the math for equating number of acid demand reagent drops to pH change.
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Or, a cheaper way would be to use your acid demand reagent to see how the color changes with each drop and then count the number of drops it takes to get to the lowest pH color on the scale (yellow).
Perhaps @chemgeek could give us the math for equating number of acid demand reagent drops to pH change.
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I found a 2 point probe in a quick internet search, http://www.omega.com/pptst/PHH_60_80.html. Seems to be much more accurate than the pH color matching routine and is not an outrageous price.
I work with lots of different test equipment, and I would think a 2-point calibration would probably suffice for most things. You would assume the device is somewhat linear over the 2-point range and you would get accurate readings. It would be offset table update of sorts. Just throwing some thoughts out there.
You will not find too much support of the digital testers here. There are a few members that use them, but most of us do not trust them. Like said before, if you get one of the expensive ones and are prepared for the calibration and replacement costs, go ahead. But there is just no need to be that accurate. Especially when you could just get a bottle of the demand reagent for a few bucks.
I agree with @jblizzle. Spending that much money on a pH probe for a pool is, well, silly (that was kind of the point of my sarcastic opening paragraph...need to start adding the [SARC][/SARC] XML markups....).
Anyway, if you get the acid demand reagent and count droplets until you see the lowest pH color, then there is a way to back-out the starting pH value. Even if you're off by 0.2, it's not a big deal.
Let's ask @chemgeek ....
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Anyway, if you get the acid demand reagent and count droplets until you see the lowest pH color, then there is a way to back-out the starting pH value. Even if you're off by 0.2, it's not a big deal.
Let's ask @chemgeek ....
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See this post for some color names Butterflly and I use for various pH levels in the phenol red pH test.
You can use the acid/base demand drops in the K-2006 to move up and down the scale, but I wouldn't try and count the drops to figure out where you were -- just use the drops to move up or down to confirm where you think you are. Now if one is color blind, that's a different issue and other than using a digital readout instrument I'm not sure what one could do.
You can use the acid/base demand drops in the K-2006 to move up and down the scale, but I wouldn't try and count the drops to figure out where you were -- just use the drops to move up or down to confirm where you think you are. Now if one is color blind, that's a different issue and other than using a digital readout instrument I'm not sure what one could do.
I bought an electronic 2 point pH meter from a wine making supply store. It is simple to operate and 1000 times easier than color matching.
However, pools need to be close not exact. Wines need to be exact, not close.
However, pools need to be close not exact. Wines need to be exact, not close.
- Jan 21, 2014
- 1,069
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
I have the same problem. I can't see the differences in color. I may end up getting an electronic ph meter, but for now I just follow the "keep it in the 7's" rule.
Hi, I am red/green colour-blind. For day-to-day testing of pH, FC, TC, CYA, TA, I use a Lovibond Scuba+ from Tintometer. It seems to have been replaced by the Scuba II, but it uses exactly the same photometric testing methodology. They claim accuracy of +/- 0.2 pH, and it always seems pretty reliable to me. I don't know about suppliers in the US or prices, but you could email them via www.lovibond.com
You can also try colored construction paper as a background with reflected incandescent or natural lighting. I find that the blues help bring out the color differences for me and, on a clear day, the bright blue sky works the best. Still not perfect, but better.
It also helps to block out the other colors on the comparator block and try to match them one at a time. There's something about the human-eye and brain that has a tendency to blend colors in close proximity but separating them makes the colors easier to compare.
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It also helps to block out the other colors on the comparator block and try to match them one at a time. There's something about the human-eye and brain that has a tendency to blend colors in close proximity but separating them makes the colors easier to compare.
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