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Thread: Pool Testing for the Color-Impaired

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    magpie's friday's Avatar
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    Pool Testing for the Color-Impaired

    So I have three questions regarding pool testing.

    First, a little background: I am not colorblind. If anything, I can see colors above and below the normal spectrum. Specifically, I have the most trouble reading the alk test because you add drops to *remove* color and there is no comparison chart. I continue to see blue, it seems, even when it's removed.

    My test results 2-3 weeks ago using Ace brand 4-way drop kit (these are the first useful readings, just after beginning borax, before adding baking soda. I have been aerating successfully all summer to keep the pH up but it dropped after turning the pump off for a week during vacation):
    FC - 3+ *
    CC (little or no change in color)
    pH - 7.4
    TA - 60 *
    CH - (untested)
    CYA - (untested)

    Pool Store's (electronic) results:
    FC - 1.8 *
    CC - .13
    TC - 1.31
    pH - 7.4
    TA - 25 *
    CH - 182
    CYA - 46
    (Borate- 10 ppm)

    --> I adjusted. pH is now 7.4, alk I read at 120, maintaining for +2 weeks. FC still reading at 3+ I'm afraid to ask the pool store to test it again, but I guess I should. The net result of using borax and baking soda is that the adjustment went perfectly, is buffering well, and @2+ days after adding borax the milky look the water always has went away completely (for a while, but I think it's my fault that it's back, so I'm not going to add that to my question list). Judging from the water quality, I did it exactly right and my pool thanked me. That suggests my numbers are right, too.

    I can't imagine I would be more than 2 drops off on the alk test or at nearly half the FC I read at home. I purchased replacement drops, thinking maybe freshness counted and maybe mine were "off" their date. The repeat test gave me precisely the same results.

    All my questions have to do with reading these tests.

    1.) Which is more likely: that this pool store's machine is out of calibration or my readings are wrong? They have the only gig in town, so I can't double check their numbers with another pool store. I'm concerned by their chlorine reading (1.8 when the drop test gave me +3) because if I raise my chemicals to 3 on the assumption that they are right, I might endanger my children's health. If I rely on my reading, then I'm keeping the chemicals too low, again unhealthy sanitation-wise.

    2.) Is there an alk drop test that matches colors, like the chlorine and pH drop test does? Or an accurate test strip? Removing the color is what throws me off. I cannot rely on my eyes when a small shadow on the background paper casts a blue tint to the water. I have been filling the chlorine side with straight water to compare and this is helping, but the differing sizes of tubes plus the different placement against the background skews the shadows and throws off my reading, still. I look like a contortionist, moving about the yard and turning upside down to compare at every angle and light source haha.

    --> My chlorine reader actually only goes up to 3. Sort of pointless. Yes, I want to maintain at around 3, but I can't read exactly how far above it is going. If I drop below 2, the water gets cloudy. I have shopped around (looked at the Taylor and T tests) and they only go up to 5, so even if I get one of these, how am I to know if I am super-chlorinating sufficiently when I "shock" for algae? (We have a lot of trees, and I do have to "shock" about every 3 weeks.)

    3.) Is there a chlorine drop test that goes above 5 ppm, and if so, is it one I can manage with color-comparison without using drops to remove color? I found the how-to-use video and the three-bottle drops for chlorine checks is confusing. Or was that only to test for combined chlorine?

    At the moment, my water is somewhat cloudy again for about a week. I generally vacuum 2X per week but the children were gone and the pool was unused, so I skipped a week and only brushed it. Brushing didn't stir up any significant algae blooms but upon vacuuming I noticed a mustard algae stuck to the bottom around the ladders that I originally mistook for sand. I scrubbed that with the broom and treated with 3 oz. of 15% polyquat 75% whatever algicide per bottle's instructions. (I know, 15% is insufficient but it's what I bought before I got to that section of the forum.) The next day, brushing stirred up a blackish dust from the bottom (dead algae?) so I vacuumed again. Will probably repeat again today, to make certain all the sub-particles I can get at are cleaned up. I do not maintain borax levels high enough to be a real deterrent to algae, since that would raise my pH too high. I do notice a green stain on my filter and the skimmer door's foam, but otherwise no green algae blooms elsewhere. I remove and spray-clean my filter at least every other day, and clean the skimmer basket at least once/daily (especially now the leaves are falling).

    I think it's time to shock again. My CC isn't bad, but I guess it's the only way to kill the goop before it turns into Algaepocalypse. I assume it's okay to use bleach to super-chlorinate a pool that's using tri-chlor tabs @ +3ppm for sanitation.

    ((Sorry. That wasn't short or painless as promised :P ))
    < 3950 ~ AG ~ Temp (Polygroup Pro Series vinyl + PVC) ~ Skimmer w/ A cartridge ~ 1.5 HP single ~ 2012

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    Mod Squad jblizzle's Avatar
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    Re: Pool Testing for the Color-Impaired

    Welcome to TFP!!!

    1. Pool store testing is notoriously bad, so hard to say if they are accurate of not. We 100% recommend doing your own testing.

    2/3. I was actually under the impression that the drop counting tests were easier for color-impaired than the color matching tests. So, I am not exactly sure what to recommend. The Recommended Test Kits so the TA are based on a color change, the test normally starts green and you count drops until the water turns red/pink. Now the color does not really matter and we recommend that you add drops until the color STOPS changing. So as long as you can see when the color is not longer changing, I would think it would work for you.

    The CH test is similar with a change from pink to blue.
    The FAS-DPD chlorine test is capable of testing up to 50ppm and is the key to the good test kits. This test starts with the water pink and you add drops until the water is clear (or at least what you would perceive as clear).

    IF the water is not clear, then you need to SLAM the pool. [slam:2iczdcog][/slam:2iczdcog] And this requires a good test kit.

    Also, you need to realize that our recommendation do not agree with pool store recommendations. The MAJOR difference is our understanding of the CYA/FC relationship. For example, if (big IF since pool stores are really bad at the CYA test) your CYA is 45ppm, according to the FC/CYA Chart. The minimum your FC should ever be is around 3.5ppm and your SLAM level to clear the pool is 18ppm.

    BTW, it is perfectly safe to swim in a pool up to the SLAM level for your CYA level. So, if your CYA is 45ppm, if is safe for the kids to swim when the FC is < 18ppm ... and in fact this would still be a lower active chlorine level than would be found in a public pool that does not use CYA.
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    Isaac-1's Avatar
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    Re: Pool Testing for the Color-Impaired

    Let me ask a follow up question here, when it comes to counting drop tests, their are 2 basic types we deal with, those that shift between a color and clear (pink to clear), and those that result in a sudden color shift (pink to blue/purple). Do you know if you have equal trouble with both types? I ask because there is the FAS-DPD drop counting FC / CC test which does go well above the 5 ppm level which relies on the pink/clear indicator. (there is sometimes a faint pink stage which means the test is close and may need 1 more drop to be at its final count).

    Ike
    Indoor 20x40 35,000 gallon vinyl pool with 1.5 HP 2 speed Jandy FloPro pump, Hayward EC75 Perflex DE filter, 11 4x12 Techno-Solis solar panels w/ Aquasolar controller, Aquabot Turbo T Robot Cleaner. Also LMI metering chlorine dispenser pump and HotSpring Jetsetter
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    magpie's friday's Avatar
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    Re: Pool Testing for the Color-Impaired

    Quote Originally Posted by jblizzle

    2/3. I was actually under the impression that the drop counting tests were easier for color-impaired than the color matching tests.
    I'm impaired in that I'm an artist. I see a spectrum range others cannot (or don't bother). My son is actually severely colorblind (and still a bangup artist @ age 8). He sees green as tan/yellow and assumes tan/yellow is green because the teacher says so. He *can* look at a shade he is told is "green" and a range of colors yellow/gold/tan and compare, picking out which is the closest shade that he sees as yellow to what he is told is green. I can't vouch for other colorblind people, but I assume based on my son's abilities, "matching" is as close to discerning colors he can't see as he can come.

    My problem is with "blue." White has shades of blue. My alk test has purplish/blue drops to add to the water, and then I add drops to neutralize the blue. The test recommends that I hold the vials in front of a "neutral" white background. The blue in the white paper tends to confuse me, as do the shadows that range into the blue spectrum.

    Quote Originally Posted by jblizzle
    The Recommended Test Kits so the TA are based on a color change, the test normally starts green and you count drops until the water turns red/pink... I would think it would work for you.
    Hully Jay, yes! Pink held against a white background is easy-pleasey. That's what I'm talking about! Thanks!

    Quote Originally Posted by jblizzle
    Also, you need to realize that our recommendation do not agree with pool store recommendations.
    Got that. I suspected as much from day one. They argued with me when I went in with my water to be tested, too. I assured them that I had the "chemicals" required to adjust my water, and then came home to consult the calculator for BB recommendations.

    Quote Originally Posted by jblizzle
    The MAJOR difference is our understanding of the CYA/FC relationship. For example, if (big IF since pool stores are really bad at the CYA test) your CYA is 45ppm, according to the FC/CYA Chart. The minimum your FC should ever be is around 3.5ppm and your SLAM level to clear the pool is 18ppm.... BTW, it is perfectly safe to swim in a pool up to the SLAM level for your CYA level. So, if your CYA is 45ppm, if is safe for the kids to swim when the FC is < 18ppm ... and in fact this would still be a lower active chlorine level than would be found in a public pool that does not use CYA.
    Okay, that scares the bejaysus out of me, though. 18 ppm? When the highest safe level with CYA according to most sources (other than pool store) is 5? Before I tell my kids to take a dip in caustic acid... No offense if I ask for second opinion to confirm?

    Quote Originally Posted by Isaac-1
    Let me ask a follow up question here, when it comes to counting drop tests, their are 2 basic types we deal with, those that shift between a color and clear (pink to clear), and those that result in a sudden color shift (pink to blue/purple). Do you know if you have equal trouble with both types? I ask because there is the FAS-DPD drop counting FC / CC test which does go well above the 5 ppm level which relies on the pink/clear indicator. (there is sometimes a faint pink stage which means the test is close and may need 1 more drop to be at its final count).

    Ike
    I use a drop test for chlorine that shows varying shades of yellow (brilliant yellow being above 3 ppm, pale yellow being 0+). My pH test shows shades of pink/peach, orange-y being low and brilliant pink being high. My alk test begins with a royal blue dye (blue on the verge of purple), adding drops to remove color to "clear" (which is a matter of perspective and shadow, plus the clarity of my "white" background which is also subjective. Maybe better to use a lower quality copy paper in this case. Bright white tends to blue spectrum.) It is the alk test, blue-removing-to-clear that I have trouble with, since there is no true "neutral" background to assist me.
    < 3950 ~ AG ~ Temp (Polygroup Pro Series vinyl + PVC) ~ Skimmer w/ A cartridge ~ 1.5 HP single ~ 2012

  5. Back To Top    #5
    Mod Squad jblizzle's Avatar
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    Re: Pool Testing for the Color-Impaired

    I think one of the recommended test kits would work MUCH better for you. All the tests are a pretty significant color change which I think you should be able to discern ... and the chlorine can be tested much more accurately and at higher levels as is required with our recommendations.

    Feel free to ask for a 2nd option about the FC levels... as long as it is on this forum No one else seems to understand the CYA/FC relationship. There are a lot of discussions about this on the forum with very detailed (over-my-head) science to back it up. Here is one: chlorine-cya-chart-t2346.html although search for something like "what chlorine level is safe" and you should find others.

    Look at this chart which shows the "active" FC level: http://richardfalk.home.comcast.net/~ri ... l/HOCl.htm
    Many public pools are not allowed to use CYA (basically due to government ignorance). They maintain the FC between 1-2ppm (look along the top row). So at a FC of 2ppm, the active chlorine (that fades your suit and dries your skin/hair) is around 1ppm.

    Now lets look at a CYA of 50ppm where we say the minimum FC is 4ppm and SLAM level is 20ppm. At 4ppm, the active chlorine is around 0.03ppm (3% of the public pool). At SLAM level of 20ppm, the active level is 0.3ppm ... that is still only 30% of the level you would "enjoy" at the public pool.

    This is why you feel so dry and you suits fade if you spend a lot of time in public pools. The CYA we use buffers the chlorine so it is not so harsh in addition to protecting it from the sun.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
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  6. Back To Top    #6
    magpie's friday's Avatar
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    Re: Pool Testing for the Color-Impaired

    Quote Originally Posted by jblizzle
    Feel free to ask for a 2nd option about the FC levels... as long as it is on this forum No one else seems to understand the CYA/FC relationship.
    Oh, heck no, I'm not looking elsewhere. I've been lurking here for over a year and gotten my most useful (accurate) info from you all. I just missed the "safe to swim at 45 ppm FC" post I guess. My most adventurous guess would have been 6 or possibly 8 ppm but I will review the suggested threads, thanks.

    I did see goal as CYA 30 and FC @ 4 ppm, ranging 3-5. That's my mantra. The pool store is over-estimating my CYA, I'm 90% certain (closer to 35).

    Um... my water isn't clear (still fighting some algae) BUT my CC is <.5. It is only .13 (according to the pool store) and I actually agree with their number on that one. At least I agree as far as it being "littler or none." I keep the pool as spotless as possible, and it's as close to 0 CC as can be without shocking (slamming?) once per week-- which I don't believe in-- I'm Greeeeeeen. (Maybe that's why I have algae haha-- green thumb. )

    Now, tell me how to get rid of the moles in my yard without trapping them or poisoning my earthworms :P

    Quote Originally Posted by jblizzle
    Now lets look at a CYA of 50ppm where we say the minimum FC is 4ppm and SLAM level is 20ppm. At 4ppm, the active chlorine is around 0.03ppm (3% of the public pool). At SLAM level of 20ppm, the active level is 0.3ppm ... that is still only 30% of the level you would "enjoy" at the public pool.

    This is why you feel so dry and you suits fade if you spend a lot of time in public pools. The CYA we use buffers the chlorine so it is not so harsh in addition to protecting it from the sun.
    This is also why I stopped taking my kids to the public pool. I have to replace their swimsuits 3X a year because the elastic goes all wonky. Too expensive. That's why I'm here... to get the results without frying out mother nature (and spending too much time at Sears).
    < 3950 ~ AG ~ Temp (Polygroup Pro Series vinyl + PVC) ~ Skimmer w/ A cartridge ~ 1.5 HP single ~ 2012

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    Patrick_B's Avatar
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    Re: Pool Testing for the Color-Impaired

    No Worries, if you follow what we show you here, you won't be out at Sears for new suits every year anymore. You'll
    have to learn to get used to a clear pool and wonder why it comes so easy.
    TFP Moderator
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    Re: Pool Testing for the Color-Impaired

    Since you asked about safe to swim levels, I'll add my $.02. My CYA is in the 60 range. I swim with FC=8 all the time. No ill effects, the water is crystal clear, and all my guests tell me how nice the water is since it doesn't have that nasty chlorine smell they associate with high levels of chlorine.

    I gave up trying to explain that the bad smell they are used to is because the water had CC, not because of the FC level.
    16,500 gallon, 18" x 38" Grecian; IG Vinyl, Hayward DE

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