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Thread: Calcium hardness to high after a year

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    Calcium hardness to high after a year

    I did a refill a year ago. My calcium Harness is now 530. I just looked back at my excel file and my first CH after refill was 220. I just looked up the city water quality report and it says 114 avg ground water and 76 average for MWD water. There is a well 1/4 of a mile away so I am guessing I get mainly well water. The pool was replastered by the previous owner in oct 99. We have been here since Aug 2000. The first 10 years or so used Trichlor and then switched to Cal Hypo. At the end I was using Pool perfect and no more phos. After the last refill the pool has had liquid chlorine mainly from Sam's Club Cloriox but Leslies Liquid chlorine when it was on sale. I use Leslies Muratic Acid. Last year I did use 50ppm borate at startup. I did try once the pool Pill liquid pool cover after my solar cover started leaving its round things in the pool. I had the pool covered except for when in use during the drought until late fall when I threw it out. $200 for a cover that lasts 15 months does not seem worth it unless we go back on strict water restrictions again. I have gone from having to clean my filter every 6 weeks to I am about to clean it for the first time since July. The pool has not been Acid washed. Do I need to do an acid wash to get the calcium hardness in control rather than just dumping and refilling the pool? I am wondering if the calcium harness is from calcium buildup on the plaster. It just seems having to dump and refill in a year is a bit often.
    14000 gal plaster in ground pool/spa;1.5 HP Hayward super 2 Emerson 3hp vsm;48 Sq Ft DE filter; liquid chlorine pump; no heater;Non working in floor pop up system; Return to Jets at steps (2) and 1 in spa.;2 Wheel Hayward Phoenix.; in Orange county CA

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    Mod Squad Texas Splash's Avatar
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    Re: Calcium hardness to high after a year

    Tough question and tougher scenario as often times water supplies are already hard in the west/southwest. Since I don't see it in your signature, can you confirm please which test kit you used to get that CH of 530? Also let us know if you used the magnetic speedstir to mix the CH reagents?

    In short, calcium from outside sources is generally from one of two places - Cal-hypo (which you stopped using) or local hard water which is very possible. Even though you received a local water report, have you tested the supply water for yourself with a TF-100 or Taylor K-2006? That would be good to know.

    As for the pool itself, can calcium from a pool change your readings? Yes, if enough has eroded from the shell itself over time and is suspended in the water. It would be good to see a full set of water test results to expand on some ideas. Can you do that for us?
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
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    Re: Calcium hardness to high after a year

    Quote Originally Posted by Santaanapoolowner View Post
    The pool has not been Acid washed. Do I need to do an acid wash to get the calcium hardness in control rather than just dumping and refilling the pool? I am wondering if the calcium harness is from calcium buildup on the plaster. It just seems having to dump and refill in a year is a bit often.
    I live in the same area as you and our tap water is hard (225-300ppm). I did a partial refill about a year ago and my pool is currently around 800ppm CH. I manage controlling scale by keeping the TA and pH lower with muratic acid. Calcium hardness does not evaporate. Every time you add tap water, the calcium hardness grows more concentrated (a tiny bit) and it adds up over time. I don't think scale on the plaster raises the CH, but is rather a symptom of high CH or a high CSI level (mainly CH, TA and pH combined).
    18,000ish gallon outdoor gunite pool & small spa (built in 1970s, re-plastered at least once)
    3HP Pentair Inteleflo VS Pump-011018; Waterway Crystal Water/Aqua Clean Cartridge Filter 570-425; Rheem 267A Gas Heater; Taylor K-2006 for pool chemistry testing

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    Re: Calcium hardness to high after a year

    Free chlorine 3.5, CC 1.0, PH7.6,TA 70, CH525, CYA40 Taylor K-2006. that was taken at 1pm. I had been only monitoring Free chlorine and PH over the winter. Last night I added 145 oz of bleach and 21 oz of muratic acid. My readings was FC1 and PH 7.8 and CH 500 with the taylor last night. Yesterday I did have to take the brush to some algee in the corners where seats meet the wall and the deep end light. I took the readings at 7PM and added the bleach then and the acid 11PM. My pump run is from 10pm to 3am.
    14000 gal plaster in ground pool/spa;1.5 HP Hayward super 2 Emerson 3hp vsm;48 Sq Ft DE filter; liquid chlorine pump; no heater;Non working in floor pop up system; Return to Jets at steps (2) and 1 in spa.;2 Wheel Hayward Phoenix.; in Orange county CA

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    Mod Squad Texas Splash's Avatar
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    Re: Calcium hardness to high after a year

    Besides the calcium concern, my gut tells me you may need to SLAM as well to rid the water of that algae. If what you saw/brushed was algae, that's no good. Plus, your CC level is elevated more than we would like. Your FC is right at the low end, so it all makes sense. If you're not convinced yet, you could also do an overnight (OCLT) test. But it's always better to SLAM now and get it out of the way quickly before it gets any worse. Just my 2 cents. At the very least right now, I'd increase the FC to about 10-12 and keep it there throughout the night.

    Your CH is elevated, but certainly understandable and not nearly as high as many others in your area who are riding closer to 1,000. So continue to keep the pH well controlled and perhaps a bit on the lower end (7.3-7.5) and don't let the TA get much higher. Do you understand the CSI concept? If not, let us know. You can see a brief snapshot of your CSI on the Poolmath Calculator near the bottom after you load all your test results. In your situation, understanding CSI and how to control it from getting too high is a good thing.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

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    Re: Calcium hardness to high after a year

    What is the CH of your refill water? Is it as low as the city reports?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Calcium hardness to high after a year

    I refilled my pool in March of 2017 after I had drained to take care of high CYA and CH. After refill, my CH was 300 from my tap and currently it's sitting at 550. You can manage your pool just fine by adjusting the other parameters (pH, TA). Some people report being able to do it with CH near or over 1000. I would not do an acid wash. It's not necessary and you could harm your plaster if not done right.

    Just keep your CSI slightly on the negative side to 0 and you'll be fine.
    Pool size: 20,000 Gallon Plaster Pool, Pump: Hayward Tristar VS SP3202VSP, Filter: Pentair Clean and Clear Plus 320
    Polaris 280 Pressure side cleaner, Solar cover, Pentair Amerilite LED pool light, Taylor K-2006C test kit
    Location: San Jose, CA

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    Re: Calcium hardness to high after a year

    So I am not looking at dumping the pool to get the CH down? I am holding off on cleaning the filter on if I need to dump the pool. the pool is cold so my CSI is -.03 target -0.32 on the pool math calculator. I have been using it for the last year and it seemed to me that during the summer when the pool water is 75-80F PH of 7.2 took the CSI below -0.6 but 7.4 was above that. If I do not need to dump I am going to vacuum the spa as it has leaves in the bottom, clean the filter and start the slam. My filter is up to almost 20 psi from 14 and if I let it get to 25 then the Phoenix cleaner really slows down as my flow gets very low. I run the pump at 55% flow to get the phoenix turns per minute of the wheels to the recommended RPM. It does climb out and suck air during the first 4 minute max flow every night.
    14000 gal plaster in ground pool/spa;1.5 HP Hayward super 2 Emerson 3hp vsm;48 Sq Ft DE filter; liquid chlorine pump; no heater;Non working in floor pop up system; Return to Jets at steps (2) and 1 in spa.;2 Wheel Hayward Phoenix.; in Orange county CA

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    Re: Calcium hardness to high after a year

    I am six months into my CH control experiment. My city's water is CH350. So my original fill six months ago was CH350. My pool is currently at CH325. My plan is to use a combination of rain water and soft water and maintain my CH at CH350-400 without ever having to exchange water (well, not for CH control, anyway). If you'd like to hear more about my adventure, I can provide details, or you can start here, where I basically told someone else the same thing, who has a similar issue as yours. Here's the post:

    Taking care of my pool - Page 11
    12300 gallon IG pebble, freeform 19x28, 1 skimmer, 3 returns, no floor drains, auto fill. Pentair: EasyTouch PSL4, ScreenLogic2, Indoor Control Panel, Intelliflo 2 VST, IntelliChlor IC40, IntellipH, CCP320 Cartridge Filter, MasterTemp 250 Heater, Rebel Suction-Side Cleaner, IntelliBrite. Solar and cleaner actuators. Heliocol HC-50 8-panel solar heating. FlowVis Flow Meter. Taylor: K-2006 and K-1766 Test Kits, SpeedStir. City/softened water.

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    Re: Calcium hardness to high after a year

    I just tested it at 240 which makes sense as my first reading after the kit arrived last year was 220, about 2 weeks after the refill.
    14000 gal plaster in ground pool/spa;1.5 HP Hayward super 2 Emerson 3hp vsm;48 Sq Ft DE filter; liquid chlorine pump; no heater;Non working in floor pop up system; Return to Jets at steps (2) and 1 in spa.;2 Wheel Hayward Phoenix.; in Orange county CA

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    Re: Calcium hardness to high after a year

    You are correct, you do not need to drain your pool. Just manage your pH and TA depending on how warm the pool water gets. In your 14,000 gallon pool with a pH of 7.4 and a TA of 70 with pool water at 72 degrees, pool math shows a CSI of -0.12. If you keep it there, you'll be fine. Even if the water warms up to 80 degrees, with the same parameters above, the CSI only goes to -0.04. I'd try it there and make any adjustments as CH continues to climb through the summer.
    Pool size: 20,000 Gallon Plaster Pool, Pump: Hayward Tristar VS SP3202VSP, Filter: Pentair Clean and Clear Plus 320
    Polaris 280 Pressure side cleaner, Solar cover, Pentair Amerilite LED pool light, Taylor K-2006C test kit
    Location: San Jose, CA

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    Re: Calcium hardness to high after a year

    OK I have shocked the pool, vacuumed it and brushed the walls. I have come across some pea sized black spots that took a metal brush to get rid of. When it broke loose there was a green ring and a brushed the ring away. Is that black Algae? I added 2 bottles of bleach for a target of 12. I am about to go to FC16. I have not yet added the muriatic acid.
    14000 gal plaster in ground pool/spa;1.5 HP Hayward super 2 Emerson 3hp vsm;48 Sq Ft DE filter; liquid chlorine pump; no heater;Non working in floor pop up system; Return to Jets at steps (2) and 1 in spa.;2 Wheel Hayward Phoenix.; in Orange county CA

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    Re: Calcium hardness to high after a year

    Headed to work so last chance for overnight and it is still at 16 with cc of .2. The water has always been clear. Before I started using TFP I always was fighting the algae in corners and on south walls. I do not know if maintaining FC at 5 helped or the Borax. I travel frequently and nobody else will pay attention to the pool only wanting to swim. I can be gone as long as 5 days at a time. After giving up on them to add chemicals I started putting a Tri-chlor tab in a floater when I left and take it out when I get back. Should I bring my Borax level back up as I have not added any over the last year. At the end of summer it was showing 30 but the test strips jump from 30 to 50. I do not know if it really helps being I went to TFP levels and borate at the same time.
    14000 gal plaster in ground pool/spa;1.5 HP Hayward super 2 Emerson 3hp vsm;48 Sq Ft DE filter; liquid chlorine pump; no heater;Non working in floor pop up system; Return to Jets at steps (2) and 1 in spa.;2 Wheel Hayward Phoenix.; in Orange county CA

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    Re: Calcium hardness to high after a year

    Don't give borates as much credit as you are. Give yourself credit for understanding the FC/CYA relationship........that is what will keep your pool sanitary and algae free.

    Your description of the black spots sounds like black algae. You have done the right thing already by brushing. Watch those spots VERY carefully for the next couple of weeks and keep your FC elevated to about 50% over what the FC/CYA chart calls for......I think that will rid you of them.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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