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Thread: Why does pool school say to test CH weekly?

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    Why does pool school say to test CH weekly?

    Why does pool school say to test CH weekly? I thought it stayed the same unless you add water.
    36 x 18 oval pool, inground, plaster pool.
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    Pool built in 1971.

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    Re: Why does pool school say to test CH weekly?

    CH can go up due to curing of plaster, or from cal-Hypo. It is important to maintain your CH levels because if it gets too high it can cause scaling (which can be really expensive to fix). Low CH can actually start to absorb calcium out of the pool walls and floors causing damage. Partial Drains and of the pool or reverse osmosis are the only ways to lower CH.

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    Re: Why does pool school say to test CH weekly?

    After a while, once you get used to the composition of your pool water, you may not need to test CH so often. But if you have: 1.) plaster less than 1 year old, 2.) cal-hypo that you use frequently, 3.) fill water that is high in calcium, you probably need to test once per week.

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    Re: Why does pool school say to test CH weekly?

    I agree with 1 & 2 but I have high CH fill water (~300 ppm) and I have found that the CH rise is very predictable and occurs fairly slowly so I usually test bi-monthly.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    Re: Why does pool school say to test CH weekly?

    I would encourage anyone who first starts to test and manage their own pool to do CH test weekly until you verify that it is stable. In most pools, it is quite predictable and you can drop back to whatever your comfort level is.

    As you open each Spring, I would again suggest a weekly test for a couple or three weeks so you can verify it's stability once more.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
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    Re: Why does pool school say to test CH weekly?

    Thanks for the info. The fill water here here is low in calcium. Before adding chemicals it was 50. I added calcium and gradually brought it up to 250. I am not using cal-Hypo, and it is an old plaster pool so I don't expect it to change based on what has been said here, but I'll test weekly for a while and see if it is stable.
    36 x 18 oval pool, inground, plaster pool.
    27000 gallons
    1 hp pump. Sand filter
    Pool built in 1971.

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    Re: Why does pool school say to test CH weekly?

    Nice work, Tom, you have become a BBB'r pretty quickly!
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Why does pool school say to test CH weekly?

    My ch has been at 350 since we filled. It has never changed. I did have my pool cover pump pumping the water into the pool over the last week to lower my salt level some, got 3" of rain. I'll test today to see if the ch went down also.
    DONE, 20 x 40, inground gunite, 30" raised bond beam with 3 12" sheer descents, 8' diving board, pentair 420 cartridge filter, vs-3050 pump, intellechlor ic-40, auto cvr, Tahoe blue pebble tech, 6ea 4' x 12.5' & 2ea 1' x 12.5' helicol solar panels, legend robotic cleaner.

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    Re: Why does pool school say to test CH weekly?

    Nice work, Tom, you have become a BBB'r pretty quickly!
    Thanks.
    36 x 18 oval pool, inground, plaster pool.
    27000 gallons
    1 hp pump. Sand filter
    Pool built in 1971.

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    Re: Why does pool school say to test CH weekly?

    After a couple days of mixing in the rain, my ch is now 310, down from 350.
    DONE, 20 x 40, inground gunite, 30" raised bond beam with 3 12" sheer descents, 8' diving board, pentair 420 cartridge filter, vs-3050 pump, intellechlor ic-40, auto cvr, Tahoe blue pebble tech, 6ea 4' x 12.5' & 2ea 1' x 12.5' helicol solar panels, legend robotic cleaner.

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    Re: Why does pool school say to test CH weekly?

    After a couple days of mixing in the rain, my ch is now 310, down from 350.
    I don't understand how this works. Does that mean that over 10% of the pool water was replaced by rain, or does it mean that the calcium is somehow removed from the water, or does it mean something else that I don't understand?
    36 x 18 oval pool, inground, plaster pool.
    27000 gallons
    1 hp pump. Sand filter
    Pool built in 1971.

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    Re: Why does pool school say to test CH weekly?

    Quote Originally Posted by TomAtlanta
    After a couple days of mixing in the rain, my ch is now 310, down from 350.
    I don't understand how this works. Does that mean that over 10% of the pool water was replaced by rain, or does it mean that the calcium is somehow removed from the water, or does it mean something else that I don't understand?
    It means that calium-rich water was replaced by calcium-free rainwater and/or the pool level went up with the rain, diluting it.
    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.
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    Re: Why does pool school say to test CH weekly?

    it just means that rain water has zero calcium in it so therefore when it rained it naturally dropped the CH level. it's my understanding based on reading this forum that calcium hardness never leaves the water unless there is reverse osmosis, partial refill or splash out.

    for example last week, i tested my CH before we were supposed to get some substantial rain. my CH was about 450 ish and i was able to capture a bit over 4 inches of rain and it lowered my CH to 400 ish. pretty close to where it needs to be. that's down from nearly 550 in early december before all of the rains have come.

    hope this helps.
    17,800 gallons, Pentair Clean and Clear 420 Cartridge Filter, Inground, Blue Granite Pebblesheen Interior, Pentair Intelliflo VS-3050 Pool and Spa pump, Pentair Whisperflo 2HP Water Feature pump, Pentair .75 HP Booster Pump for Pentair Legend pool cleaner, Pentair EasyTouch 8-function remote, Pentair IntelliChlor SWG.

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    Re: Why does pool school say to test CH weekly?

    Quote Originally Posted by TomAtlanta
    After a couple days of mixing in the rain, my ch is now 310, down from 350.
    I don't understand how this works. Does that mean that over 10% of the pool water was replaced by rain, or does it mean that the calcium is somehow removed from the water, or does it mean something else that I don't understand?
    I was surprised how much it went down, in hind site I prob should have left it at 350 because at 310 my csi is approx -.50.
    DONE, 20 x 40, inground gunite, 30" raised bond beam with 3 12" sheer descents, 8' diving board, pentair 420 cartridge filter, vs-3050 pump, intellechlor ic-40, auto cvr, Tahoe blue pebble tech, 6ea 4' x 12.5' & 2ea 1' x 12.5' helicol solar panels, legend robotic cleaner.

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