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Thread: Vanishing chlorine and plaster stains? UPDATE w/ TF100 results

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    Vanishing chlorine and plaster stains? UPDATE w/ TF100 results

    Hey everyone, first post here. Wife and I bought a house and immediately had a pool (see my sig) built in our backyard this spring. Here are the latest test results:

    FC: 0 - tested by me
    CC: ? - not tested
    pH: 7.6 - tested by me
    TA: 80 - tested by me
    CH: 210 - tested by pool store
    Borates: Not using (yet).
    CYA: Tested by pool store 3 times in the last week ... got 80, 70, and 35, in that order. <--- More on this below
    Phosphates: 0 - tested by pool store (we put in phosphate remover 2 weeks ago)
    Iron: 0 - tested by pool store
    Copper: 0 - tested by pool store

    Here's a 2-part problem we're having.

    1) I've been putting trichlor tabs in the puck tower and been leaving the chlorinator on, trying to maintain FC at 1-2 ppm per instructions from my pool builder. My chlorine has been all over the place, more often too low (near 0), however. I only have a basic color matching test. We did have CYA added along with metal remover once the pool was built. We thought at first we did not have enough stabilizer and was losing excessive Chlorine to the sunlight. We don't have much shade around the pool, if at all. So we added more CYA last week. Then I switched over to bleach (Tandil 8.25% sodium hypochlorite from Aldi's) and tried to shock the pool that way. In order to rule out sunlight, I added it after sunset last night, and the next morning, the FC was almost gone. Which leads me to my next point...

    2) We have plaster stains of what I think are algae. I might want to post an actual pic, but the stains look grayish and won't brush off. I only notice them on a cloudy day, or shadowed from direct sunlight. The water itself is clear, and when we have direct sunlight, it looks beautiful, blue, and sparkling. At first glance, my pool may look normal and quite swimmable, I'm not fooled by its appearance, I know and feel something just isn't right. I'm just not sure if the stains ARE algae, or if it's something else like metals (but with algae still floating around in the water, as the overnight FC test showed me).

    Let me rewind to last week... we talked to the pool store, and they told us to turn off our chlorinator and use shock instead, because the pucks contain stabilizer (WHY?!), so we may end up having too much CYA and may have to drain half the pool and refill! Before we talked to the pool store, we didn't know any better and we had already added more stabilizer thinking it was the sunlight that was killing our FC - that may have been a big mistake. Before we added extra stabilizer, our CYA was already at 80 as of last week per store's test results. Now, the weird part is, we tested CYA two more times... 70 a few days ago, and 35 yesterday. That was AFTER we added more stabilizer 4 days ago.

    Maybe I shouldn't trust the pool store's test results. I just ordered the TF100 test kit and it's on its way soon, so I can test everything myself and see the results with my own eyes.

    I'm afraid my CYA levels are too high, and may have to drain part of the pool, and then do a SLAM. So I looked at my instructions packet from the builder, and with regards to draining, it says:

    "Pools with a hose bibb at the equipment pad that is used to drain your pool when necessary. Should the water rise to the top of the tile line or above, attach a hose to the hose bibb, turn on your circulation pump and turn on the hose bibb to lower your water level. Your target water level is the middle of the waterline tile. When that tile line is even with your water level, turn off the hose bibb. DO NOT FORGET!!"

    Can anyone explain to me what this means?

    To summarize, here are my questions:

    1. Why are there grayish splotched stains on my plaster? it seems to be getting worse with time. If it's algae or metals, what are the ways to remove such stains?
    2. How do I drain a pool? What equipment is needed, where do we dispose of the water, and how much will it cost?
    3. I have friends coming over this weekend, and I don't want to drain and SLAM before they come. But how do I keep the chlorine levels up to keep algae from getting worse?

    I'm sorry for the rambling, long and confusing post. That should tell you how confused I am!
    IG gunite pool size: 12,500 gallons - includes spa with spillover, Polaris vacuum cleaner, Ultrapure Ozonator, inline tab chlorinator that I no longer use
    Filter: Hayward Swimclear Model #4030, 4-Cartridge Filters
    Pump: Century, 2 HP with a Hayward 6060 booster pump
    Date of build: March-April 2014 *NEW* : Test kit: TF-100

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    Richard320's Avatar
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    Re: Vanishing chlorine and plaster stains?

    Welcome!

    Boy, that's some first posting! I won't even attampt to address the chlorine loss questions without reliable test results, which you'll have soon. Congratulations on learning not to trust the store results so soon in your ownership!

    The stains sound like they could be metal or Calcium. Or metal-stained Calcium. Maintaining a low pH and brushing with a stainless steel brush may slowly remove them. Wait for the test results, though.

    For the immediate problem, they way to keep the chlorine level up is to add more. And frequently. It's hard to say what the SLAM level would be, since CYA could be anything. But if you target 14, which is SLAM level for the lowest reported CYA, it should at least keep things from getting worse.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Re: Vanishing chlorine and plaster stains?

    Thanks Richard320 for your reply. I did a quick test to see what the stains were. I got a small 1" trichlor tab and held it against a stained pool wall for 1 minute. When I removed the tablet, the area against the tablet lightened up significantly. Definitely has to be algae, which explains total chlorine loss overnight after putting in 2 gallons worth of bleach the night before.

    What if I were to re-shock my pool using the highest known CYA levels tested (80), which means adding in 31 ppm of FC? Is there any harm in trying it tonight just to see what happens?

    Here are some pics of my pool (stains aren't noticeable in direct sunlight, but unsightly when shadowed...):

    Attachment 29551

    Attachment 29552
    IG gunite pool size: 12,500 gallons - includes spa with spillover, Polaris vacuum cleaner, Ultrapure Ozonator, inline tab chlorinator that I no longer use
    Filter: Hayward Swimclear Model #4030, 4-Cartridge Filters
    Pump: Century, 2 HP with a Hayward 6060 booster pump
    Date of build: March-April 2014 *NEW* : Test kit: TF-100

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    Richard320's Avatar
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    Re: Vanishing chlorine and plaster stains?

    The trichlor test isn't conclusive. Trichlor is very acidic, and it will leave big white spots on plaster if a puck sits there. It can etch away scale and dissolve metals.

    A better test is a Vitamin C tablet. Plain Vitamin C. You might have some, or can get some from a health fiend/hypochondriac friend or just buy the cheapest generic you can get at the drugstore. Set one on a stain for a couple minutes. If you see a tablet-sized white spot, it's metals. If no change, then it could be Calcium or Algae. Test results would probably help make an educated guess which.

    If you want to blast it with chlorine, it's your pool. Gunite won't fade like a vinyl pool will if the FC is too high. But that one-time blast may not kill it all if it is algae. I don't suppose it will hurt anything but your wallet. Do note that super high FC will skew test results. Test strips have been known to bleach out, showing zero FC when it's actually way high! And the drop pH tests will read falsely high above 10 FC. So if you do try the nuclear option, don't even bother testing anything tomorrow. Give it a day to come down.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Re: Vanishing chlorine and plaster stains?

    Thanks again. Did the vitamin C test - no color change. I think this pretty much confirms algae.

    Blasted my baby with 4.5 jugs of 8.25% bleach, FC should go up to about 30.

    Since I don't have the FAS-DPD yet, I'll dump another jug in the morning, and then repeat the process tomorrow night. I should get the test kit by thursday evening, so I will reassess then.
    IG gunite pool size: 12,500 gallons - includes spa with spillover, Polaris vacuum cleaner, Ultrapure Ozonator, inline tab chlorinator that I no longer use
    Filter: Hayward Swimclear Model #4030, 4-Cartridge Filters
    Pump: Century, 2 HP with a Hayward 6060 booster pump
    Date of build: March-April 2014 *NEW* : Test kit: TF-100

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    Re: Vanishing chlorine and plaster stains?

    SLAM Day 1, water is very clear. FC still very high, CC is close to 0, but I need a more precise test than the one I have. I admit I'm flying blind and just guessing. I did see some gray spots on the pool floor, and easily swept them away - could be dead algae. Most patches/stains still don't brush off, but they look a little better/lighter. Could just be my wishful thinking, though.

    Dumped another jug and a half in, and will continue to SLAM until I get that new test kit. Then I will know exactly where I am. Will also get a stainless steel brush, get in there, and really brush against the stains.
    IG gunite pool size: 12,500 gallons - includes spa with spillover, Polaris vacuum cleaner, Ultrapure Ozonator, inline tab chlorinator that I no longer use
    Filter: Hayward Swimclear Model #4030, 4-Cartridge Filters
    Pump: Century, 2 HP with a Hayward 6060 booster pump
    Date of build: March-April 2014 *NEW* : Test kit: TF-100

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    Re: Vanishing chlorine and plaster stains?

    Quote Originally Posted by yardoasis View Post
    ......... Will also get a stainless steel brush, get in there, and really brush against the stains.
    You might hold off on that stainless steel brush for awhile. I think I read on here that a new pool should be fully cured before using one. Maybe one of the more experienced members can give more clarification.
    14K Gallon IG Gunite Pool built in 2005, Century Centurion 1 1/2 HP Pump
    Pentair Clean & Clear 420 Sqft. Cartridge filter, MiniMax Pentair NT Heater, The Pool Cleaner
    Taylor K-2005 test kit with Taylor K-1515-A FAS-DPD Chlorine Test. SpeedStir

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    Re: Vanishing chlorine and plaster stains?

    Had to stop the SLAM because I'm having issues with the pump... had to turn it off until I figure out what the problem is...

    http://www.troublefreepool.com/threa...038#post648038
    IG gunite pool size: 12,500 gallons - includes spa with spillover, Polaris vacuum cleaner, Ultrapure Ozonator, inline tab chlorinator that I no longer use
    Filter: Hayward Swimclear Model #4030, 4-Cartridge Filters
    Pump: Century, 2 HP with a Hayward 6060 booster pump
    Date of build: March-April 2014 *NEW* : Test kit: TF-100

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    Re: Vanishing chlorine and plaster stains?

    Got the TF100 test kit! Wheee!! Feeling like a kid on Christmas morning!

    Without further ado, here they are:

    CYA: 45 (soooo relieved that I don't have to drain and refill! could be as low as 40 depending on how I hold the tube and the lighting, but going with 45 for now)
    FC: 15.5 (was in the middle of SLAM)
    CC: 1.0
    CH: 375 (should be 200-400, so I'm near the high end... is that a problem? anything to do with the staining problem that I'm having?)
    TA: 130 (could be a false high reading as I'm in the middle of a SLAM and the testing instructions says the first time I test could be incorrectly high, will retest when I'm done slamming)

    Didn't bother to test pH, but it was 7.6 when I started the SLAM. Plugged all these numbers into PoolMath with a temp of 80 degrees, and got a CSI of 0.33, says potential to become scaling. Hmm...

    What do you all think?
    IG gunite pool size: 12,500 gallons - includes spa with spillover, Polaris vacuum cleaner, Ultrapure Ozonator, inline tab chlorinator that I no longer use
    Filter: Hayward Swimclear Model #4030, 4-Cartridge Filters
    Pump: Century, 2 HP with a Hayward 6060 booster pump
    Date of build: March-April 2014 *NEW* : Test kit: TF-100

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    Richard320's Avatar
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    Re: Vanishing chlorine and plaster stains? UPDATE w/ TF100 results

    SLAM SLAM SLAM SLAM SLAM SLAM

    The false high TA is caused by static electricity on the tip of the reagent. Wipe it with a damp paper towel between drops. Extended Test Kit Directions.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Re: Vanishing chlorine and plaster stains? UPDATE w/ TF100 results

    Ok, I'll take my FC up to 20 now. With a CYA of 45, I have a SLAM level of 18... so I'll go a little above that, retest tomorrow, and post back.
    IG gunite pool size: 12,500 gallons - includes spa with spillover, Polaris vacuum cleaner, Ultrapure Ozonator, inline tab chlorinator that I no longer use
    Filter: Hayward Swimclear Model #4030, 4-Cartridge Filters
    Pump: Century, 2 HP with a Hayward 6060 booster pump
    Date of build: March-April 2014 *NEW* : Test kit: TF-100

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    Re: Vanishing chlorine and plaster stains? UPDATE w/ TF100 results

    Morning test results:

    FC: 22
    CC: <0.5

    I added a generous amount of bleach last night, and might have overdone it a little. The fact that the pool is holding chlorine is encouraging, and I'm 99% convinced that I passed the OFCT. Water is crystal clear.

    CC is much better, it barely turned pink I had to look at it from different lighting angles to see the faint pink hue. One drop got rid of the pink, but the test precision is 1 drop = 0.5 ppm, so I'm going to say less than 0.5. My hand doesn't smell after dipping it into the pool getting a sample... it smelled last night.

    I think I'm pretty much done with the SLAM? Now how to tackle the stains, which still look pretty much the same? I'm starting to think it's something else other than algae.
    IG gunite pool size: 12,500 gallons - includes spa with spillover, Polaris vacuum cleaner, Ultrapure Ozonator, inline tab chlorinator that I no longer use
    Filter: Hayward Swimclear Model #4030, 4-Cartridge Filters
    Pump: Century, 2 HP with a Hayward 6060 booster pump
    Date of build: March-April 2014 *NEW* : Test kit: TF-100

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    Re: Vanishing chlorine and plaster stains? UPDATE w/ TF100 results

    Looking back on my pre-TFP days when I was using trichlor tabs, I remember always fighting high pH. I have had to add muriatic acid almost daily because the pH always trended towards 8.0, and the stains appeared as the temperatures got warmer. With that 375 CH reading and a CSI of 0.33, do I have reason to believe that I have calcium scaling?
    IG gunite pool size: 12,500 gallons - includes spa with spillover, Polaris vacuum cleaner, Ultrapure Ozonator, inline tab chlorinator that I no longer use
    Filter: Hayward Swimclear Model #4030, 4-Cartridge Filters
    Pump: Century, 2 HP with a Hayward 6060 booster pump
    Date of build: March-April 2014 *NEW* : Test kit: TF-100

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    Re: Vanishing chlorine and plaster stains? UPDATE w/ TF100 results

    Tested CYA just to make sure, got 45-50 again. So I'm ok there.

    FC dropped to 14.5 from this morning, pretty large drop on a partly cloudy day. Improvement in CC, I'd say it's less than 0.2 now. Very very faint pink hue... would have said it's clear if I didn't look very carefully.

    I don't think I'm quite done with the SLAM just yet. One more day, maybe. Added some bleach and will take another FC test tonight before I go to bed so I have a baseline for the OFCT test.
    IG gunite pool size: 12,500 gallons - includes spa with spillover, Polaris vacuum cleaner, Ultrapure Ozonator, inline tab chlorinator that I no longer use
    Filter: Hayward Swimclear Model #4030, 4-Cartridge Filters
    Pump: Century, 2 HP with a Hayward 6060 booster pump
    Date of build: March-April 2014 *NEW* : Test kit: TF-100

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