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Thread: how do these numbers look?

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    how do these numbers look?

    First, I must say that I too am now a believer in using a good test kit..and this is only the second year with a pool! That said, would just like to know if I'm on the right track here. Pool size = 22,500 gal, above ground vinyl (next have to figure out how to add info show it always appears...but first things first).

    FC= 2.5
    CC=0
    TC=2.5
    pH = 7.0 (?)
    T/A = 140
    CH = 120
    CYA= 33-35 range
    temp = 70

    OK, here's what I think I know from reading pool school charts, etc. My FC is at the low end but ok with my CYA level. Calculator says optimal is 4 so will add gal of bleach. My ph is low because I lowered from 7.8 to get first reading of TA down from 170, which it did. Today, I am aerating by turning return valve upward to break surface. Would like to get to get TA down to 120, is that correct? And this aeration will only raise pH and do nothing to TA, correct? Once pH is back up, I will lower it again to try to drop TA from 140 to 120 (or is the 140 OK?). And CYA is OK, where it is, correct (and shouldn't need to test this again unless massive rains, true?). The only problem I have with the TF kit is that it seems as though there should be a more accurate way to test pH. I can't tell exactly where the color is on the vial...it's a very pale orange so seems somewhere between the 6.8 and 7.2 range, but hard to tell. All I know is, it's low. Any ideas?
    22,500 gal A.G., vinyl, sta rite cristal sand filter & pump (1.5 h.p.), BBB method

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    JasonLion's Avatar
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    May 2007
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    Silver Spring, MD
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    Re: how do these numbers look?

    Your PH is low and should be raised. If you are using trichlor tablets you want to raise your PH to 7.8. If you are using any other source of chlorine you only need to raise PH to between 7.2 and 7.4 and it will probably drift up the rest of the way on it's own.

    With CYA around 35 you never want to allow FC to go below 3. That means you need to raise it up to somewhere around 6, so that by the time you get back to testing and adjusting FC it won't have fallen too low.

    What kind of pool do you have? If you have a plaster/quartz/pebble pool you want to raise CH up to at least 250.

    It would be helpful if you could put some basic specs for your pool in your signature.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  3. Back To Top    #3

    Re: how do these numbers look?

    I'm not sure how to add the pool info to my signature, so you will notice that I listed my pool specs in my actual post. It is a vinyl above ground. I did forget to add that I do use BBB method. I was using the CYA/Cl chart to determine that at CYA at 32ish then the min Cl should not go below 2, and opt is 4. So should I not use this chart? I know I needed to get the Cl up, but should I always shoot for 2 numbers above the best level for Cl to allow for drifting?

    Any suggestions then on how to determine exactly what my pH is? It may be 7.2. I have a very hard time determining the actual shade. We do not use the trichlor tabs.
    22,500 gal A.G., vinyl, sta rite cristal sand filter & pump (1.5 h.p.), BBB method

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    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,887

    Re: how do these numbers look?

    The minimum FC level is just that, a minimum. You never want the FC level to fall below the minimum. The target FC level is an approximate FC level that you can aim for, so that 24 hours later the FC level will still be at or above the minimum. The actual level you should target in your pool will vary depending on the water temperature and the bather load. The idea is to pick a number so that 24 hours later it is still at or above the minimum.

    Your TA is probably fine where it is now. Only lower your TA level if you are having problems with PH drifting up.

    If you view the PH tube in bright indirect light you can often distinguish the colors better. It does take some practice. For now, if it is between 6.8 and 7.2, adjust it so it is between 7.2 and 7.5. After a while you will get better at reading the colors.

    You can setup your signature by clicking on the User Control Panel link, just under the TFP logo. Then click on profile, on the left, and then click on signature.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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