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Thread: Help! My calcium hardness continues to rise

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    Help! My calcium hardness continues to rise

    Pool was installed in 2013, plastered and opened 4/2014, this is my third season as a pool owner, and have had nothing but problems since opening the pool last May. We opened the pool to find the entire pool and spa scaled, even though we had the maintenance company test the pool water monthly and adjust pH. The pool maintenance company added acid to the water to remove the scale, that was done in May 2015. Since 2014 I've battled high pH, high Cyanuric Acid in 2015 too. In August I noticed some residue on the walls of the pool, when rubbed it came off. I called the maintenance company and had the hardness tested, it was 550, all season up to August the hardness according to the pool store was within normal limits. September 25 we had 3/4 of the water removed from the pool and a water hauler refill the pool, the hardness was 190. 9/28 we closed the pool. I elected a winter watch program to test the water due to the problem with high pH and now the hardness level. The water was tested and 11/4 the hardness was 400, hardness and the pH continued to rise all winter. Acid was added to the pool to lower the pH and a pump circulated the water when acid was added during the winter. We opened the pool 4/25/16 to the spa scaled and chipped, the hardness was 500. I'm at my whits end, no one seems to know why the hardness keeps climbing. We looked at every product I've used and nothing contains calcium. Now the pool company that installed the pool is telling me to continue to drain 2 feet and refill the pool over the next month or two to lower the hardness, that just seems ridiculous as we did that last September and in November the level was up to the max. It will cost a fortune to continue to drain, add water and re-balance chemicals! In the past year I've spent almost $10,000 in pool chemicals and with the maintenance company to correct issues. Does anyone have a suggestion as to why this is happening and a possible solution? Thank you!
    Susan
    20,000 gal in ground free form white plaster pool
    Spa with spill over. SWG pool with DE filter and heat pump.

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    Mod Squad JVTrain's Avatar
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    Re: Help! My calcium hardness continues to rise

    Welcome to TFP!

    It would be very difficult to tell without solid chemistry numbers... not the one from the pool store or maintenance company. You're own numbers with you're own test kit. Check out the recommended test kits here: Pool School - Test Kits Compared The TF-100 is the best value and has all the tests you need (tfteskits.net). The K-2006 is passable but not as many reagents for the price.

    What we teach here is pool owners taking control of their own pools. A recommended home test kit is required for us to give advice.

    Check out this article as well as the ABCs of Pool Water Chemistry in Pool School to get started. Pool School - Calcium Scaling
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
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    Re: Help! My calcium hardness continues to rise

    I use a Taylor Test kit. My numbers yesterday were FC 1.5, pH 7.5, Alk 80, Cya 30, CH 290-300. The pool temp is about 73 degrees. I test my pool water every day. As a note, I am not currently running the salt system.
    Susan
    20,000 gal in ground free form white plaster pool
    Spa with spill over. SWG pool with DE filter and heat pump.

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    Mod Squad pooldv's Avatar
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    Re: Help! My calcium hardness continues to rise

    Welcome to TFP!

    What is the CH of the fill water? There are really only two ways for CH to rise, high CH fill wafer or using cal-hypo to chlorinate/shock the pool.

    It is fairly easy to manage your water chemistry to avoid scale, even with CH above 1000 ppm. Enter all your test results in Poolmath and it will calculate the CSI of the water. Keeping the CSI slightly negative, 0 to -0.3, will prevent scaling and also help your plaster and SWG last longer. If you currently have some scale you can hold CSI at -0.5 to -0.6 and brush the scale to gently and slowly remove the scale. It could take weeks to months depending on how long the scale has been building up. But, it is a lot better for your plaster than an acid wash. Acid wash is very aggressive and will shorten the life of your plaster. You can also use wet/dry sandpaper on rough scale to smooth it.

    More here, Pool School - Calcium Scaling
    and here, Langelier and Calcite Saturation Indices (LSI and CSI)

    What is your TA? If it runs high, above 100, it can contribute to PH rise. Letting it drop to 60 or 70 will help slow PH rise. Aeration from waterfalls, bubblers, etc also contribute to PH rise. Running them less will help.
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    Re: Help! My calcium hardness continues to rise

    Susan, welcome to TFP

    You have been on a pool company and store ride to long, lets get you off the money bus and let you keep it for a vacation with the family

    How does your water look now? Grab a test kit but depending on how your water looks will depend on what test kit is recommended...

    If your green recommend the TF100 with XL option and the speedstir (the speedstir will be a lifesaver testing your high CH)

    If not green water just get the TF100 with speedstir

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    Mod Squad JVTrain's Avatar
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    Re: Help! My calcium hardness continues to rise

    Quote Originally Posted by Susan Rossi View Post
    I use a Taylor Test kit. My numbers yesterday were FC 1.5, pH 7.5, Alk 80, Cya 30, CH 290-300. The pool temp is about 73 degrees. I test my pool water every day. As a note, I am not currently running the salt system.
    Based on those numbers, your CSI is about -0.3 Not likely an issue for scaling, leaning a bit corrosive. Do you have a historical record of test results in a spreadsheet or otherwise? If at some point your CSI was negative over a period of time, you could actually have been leeching calcium from the pool plaster.

    Incidentally, your FC is too low for your CYA based on TFP recommendations. See the CYA/Chlorine chart in my signature.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
    Isolated Spa - 345 Gallons

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    Re: Help! My calcium hardness continues to rise

    Thank you for the response, and information. The fill water hardness is about 70. The scale in the spa has been brushed off, thankfully it wasn't bad. The TA is currently about 80, we do have a spa with spill over. I will let the TA drop a bit, I was trying to keep it to 80. I will see what the CSI reading is. Thank you again!!

    - - - Updated - - -

    The pool water always looks great. Thankfully I have a sparkling clear pool! I'm not going to bother to have the water tested at the pool store, thanks!!
    Susan
    20,000 gal in ground free form white plaster pool
    Spa with spill over. SWG pool with DE filter and heat pump.

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    Re: Help! My calcium hardness continues to rise

    A couple thoughts I had when reading your post

    1) You're using the large sample where every drop equals 10 CH. When numbers get high like yours, use the 10 ml sample, 10 drops of R-0010, 3 drops of R-0011 (I use 5 for deeper colors) and each drop of R-0012 is 25 CH. Close enough and it saves a lot of reagent and swirling
    2) If you're swirling by hand, get a speedstir. The test is much more accurate and your arm doesn't get tired. My CH readings dropped almost 200 points just by switching to the speedstir.
    3) Even if your CH really is 500, that's not so bad. Play with poolmath a little. Plug all your numbers in and check CSI. Then one at a time, alter each parameter and see how it affects the CSI. You'll see that even huge jumps in CH don't make as much difference as pH, TA, and temperature. Keep the pH and TA in line and you should be fine.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
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    Re: Help! My calcium hardness continues to rise

    Welcome to the forum.

    If you have a fill water hardness of 70 ppm and a pH of 7.5, scaling in your pool is a virtual impossibility.

    There is another possible source (not really) if you are using Calcium Hypochlorite to sanitize your pool. Are you?

    High CH in pools only shows up if you put it there. Either by the CH of your fill water or the CH in Cal Hypo.

    Something is not adding up.....You reported the CH as 500 on 4/25 and yesterday your report 290-300.

    One of those numbers is wrong, unless your fill water really is 70 ppm. That would mean you are DECREASING CH....not adding to it.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Help! My calcium hardness continues to rise

    The scaling in the pool happened over the winter 2013-2014, the pH continued to rise and the pool company continued to add acid to lower it. It was a bad winter in NJ and the pool was covered with snow, so the pool water couldn't be tested nor could it be treated with acid.

    I do not use Calcium Hypochlorite, I use Lithium. We looked at all of the products I used and nothing contained calcium.

    Following the 500 reading we took 2-3 feet of water off the pool and filled with house water, which has the 70 ppm. I agree something still doesn't add up.
    What is troubling for me is that after taking 3/4 of the water off the pool in September, having the CH at a reasonable level, covering the pool, only to have it go up to 400 in November. At that time the pH also went up to 8.2. I don't understand how those two numbers could increase so dramatically in a little over a month, that's what I've asked the pool manufacturer, and the pool maintenance company, they can't tell me and I'm at a loss.
    Susan
    20,000 gal in ground free form white plaster pool
    Spa with spill over. SWG pool with DE filter and heat pump.

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    Re: Help! My calcium hardness continues to rise

    Thanks for the suggestion. I have also been struggling with the pH. Last year I added pH down on a daily basis, which is why I had the maintenance company come every couple of weeks over the winter to pull the cover back and test the water to keep an eye on the pH and CH.
    Susan
    20,000 gal in ground free form white plaster pool
    Spa with spill over. SWG pool with DE filter and heat pump.

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    Re: Help! My calcium hardness continues to rise

    The test numbers you are reporting and the results you are reporting just don't work.

    I'm gonna' repeat something already posted by pooldv. Calcium can only get in your pool if YOU put it there. It cannot rise on it's own. It cannot rise on it's own.

    So, that leads us to some inescapable information..... the test results are bogus or someone is secretly slipping Cal Hypo or Calcium Carbonate into your pool.

    I would start by doing your own testing......something is wrong and you need to eliminate testing errors.

    Secondly, with a fill water of 70 CH, the CH in your pool should actually be going down....not up.

    I think you need to get a handle on the testing by doing it yourself......There's no way that what you are reporting can be happening. Eliminate the middle guy as a source for error.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Help! My calcium hardness continues to rise

    I do my own testing, each day everyday, I use a Taylor Test kit. The CH has gone down since we took a few feet of water off the pool and added fill water from the house.
    I am the person taking care of this pool and when the pool maintenance company comes to the house, when they opened the pool for example, I'm here and I always go out to see what they're doing and I ask a lot of questions. I've contacted the pool builder and brought up the possibility of an issue with the plaster. I looked at every chemical I have put into this pool and nothing contains calcium.
    I don't know how the CH went up after the pool was closed last September, that's the question I've asked over and over, which is why I posted the question on this site.
    Susan
    20,000 gal in ground free form white plaster pool
    Spa with spill over. SWG pool with DE filter and heat pump.

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    Re: Help! My calcium hardness continues to rise

    The CH has gone down since we took a few feet of water off the pool and added fill water from the house.
    If you reported that I missed it. What was it before and what did it go down to?

    Please don't shoot the messenger. I can only comment on what is posted and your posts implied (to me) that you had a pool service doing the testing. My only interest is eliminating the variables to try and find reasonable explanation of the results reported.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Help! My calcium hardness continues to rise

    When the pool was first opened 4/25, I did not have the Taylor Test kit so I did not have the ability to check CH, I always tested ether levels using Pentair (I think that's the name). The pool maintenance guy had the Taylor kit, he tested CH at 500, could it be wrong, sure. After that reading we took about 3 feet of water off the pool and filled it with house water the house tested at 70, tested after the partial drain at 300, I tested it. I took another foot of water off and its now testing at 270 - 275, I'm testing CH frequently now along with everything else. I hope we stay at that level, but I'm worried after what happened in September, especially since no one seems to be able to figure out why it happened.

    To clarify last year I would go to the pool store to check the water, as a double check of what I was getting, that is no longer the case I'm relying on my numbers.

    Thank you, I've been pretty frustrated with this situation.
    Susan
    20,000 gal in ground free form white plaster pool
    Spa with spill over. SWG pool with DE filter and heat pump.

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    Re: Help! My calcium hardness continues to rise

    Another development from my original post. After opening the pool this year and finding scale in the spa the pool company representative came out twice and polished the spa. The second time, 5/4 it was smooth. I just went out to test my water chemistry and the spa is now rough. Of course I've contacted the pool installer who is supposed to come out on 6/6 to polish all the chips in the spa, but now with this new development the entire spa will need to be polished. However, I think it should be re-plastered. I'm at the end of my rope with this pool. I test every day, my pH continues to rise and I add pH down daily. Today it was high, 7.8 - 8.0 this morning, I added 1 1/2 lbs of down yesterday morning it was about 7.6. My CH is between 280-300, and the TA is about 75-80, Cya is 40.
    This is only our third season! I don't know what could be wrong with this pool, any thoughts, or suggestions would be appreciated.
    Note: Just looked at my records, pH yesterday was 7.8, not 7.6.
    Susan
    20,000 gal in ground free form white plaster pool
    Spa with spill over. SWG pool with DE filter and heat pump.

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    Re: Help! My calcium hardness continues to rise

    You shouldn't be having those problems with those test results. The funny thing is, your CH is actually low for your environment. 350-450 would be in range.
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    Re: Help! My calcium hardness continues to rise

    Quote Originally Posted by Susan Rossi View Post
    I add pH down daily.
    Is Muratic Acid not available in your area?
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    Re: Help! My calcium hardness continues to rise

    Yes it is, I will use it going forward. Also the pool walls seem to be bumpier in spots, I don't remember that last year. I'm so frustrated.
    Susan
    20,000 gal in ground free form white plaster pool
    Spa with spill over. SWG pool with DE filter and heat pump.

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    Re: Help! My calcium hardness continues to rise

    I agree, I especially shouldn't be having these issues with this being my third season!
    Susan
    20,000 gal in ground free form white plaster pool
    Spa with spill over. SWG pool with DE filter and heat pump.

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