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Thread: pH Testing Question

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    pH Testing Question

    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.
    16K gallon in ground plaster pool
    Hayward star clear plus c1202 Cartridge filter
    4 speed Pentair Intelliflo Pump
    TF-100 w/Speed Stir
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    Mod Squad jblizzle's Avatar
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    Re: pH Testing Question

    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.
    Jason, TFP Moderator
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    Re: pH Testing Question

    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.
    16K gallon in ground plaster pool
    Hayward star clear plus c1202 Cartridge filter
    4 speed Pentair Intelliflo Pump
    TF-100 w/Speed Stir
    Manual Brush and Vacuum

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    Mod Squad jblizzle's Avatar
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    Re: pH Testing Question

    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.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
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    pH Testing Question

    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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    Re: pH Testing Question

    Quote Originally Posted by SunnyOptimism View Post
    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.


    Sent from my iPhone using Tapatalk
    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.
    16K gallon in ground plaster pool
    Hayward star clear plus c1202 Cartridge filter
    4 speed Pentair Intelliflo Pump
    TF-100 w/Speed Stir
    Manual Brush and Vacuum

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    Mod Squad jblizzle's Avatar
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    Re: pH Testing Question

    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.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
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    Re: pH Testing Question

    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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    Re: pH Testing Question

    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.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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    Re: pH Testing Question

    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.
    16 x 32 17500 gallons
    Vinyl in-ground
    Hayward 250# Sand Filter
    1 HP Pump
    Hayward SWG

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    Re: pH Testing Question

    Have someone in your family or a friend match the color. No charge. LOL
    14,700 gallons IG Pool Vinyl Liner - Octal Circulation System
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    Re: pH Testing Question

    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.
    IG gunite/plaster pool/spa Started 1/17/14, Plastered 5/16/14
    Size: 12'-21'x39' free form, depth ranging from 4' to 7, attached 6 person spa with spillover.
    Equipment: Whisperflo 2hp pump, Pentair 30" sand filter, Pentair Mastertemp 400k BTU heater, 1hp Whisperflo for waterfalls, and a blower for spa floor

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    Re: pH Testing Question

    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
    20K painted concrete (white) IG, Californian beach down to 4.5' freeform, Rock/stone wall and waterfall on 1 side
    Hayward SP2616VS pump Triton TR100 sand filter, Aquabot Aquaclean robot

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    pH Testing Question

    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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