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Thread: help with Ph levels and Muriatic acid

  1. Back To Top    #1
    thehappylittlelady's Avatar
    Join Date
    Jul 2015

    help with Ph levels and Muriatic acid

    testing results from this evening
    CYA 50 / TA 240 / PH 8.4 / FC 3 / TC 3/ TH 100
    16 x 16 x 4 ( but at an angle ) round above ground Coleman pool ( I don't know what kind of filter its a round filter I have to rinse out or replace every 2 weeks or so)

    I have about 1 month experience with a pool. I have only used the bbb method i found it accidentally when looking up how to treat my water (after the pool was set up for a few days, in our excitement we rushed it a bit). My numbers were good and I was adding 1 Gallon of bleach in the morning sometimes another in the afternoon because it was back at 0. I had acid but put off using it at first.
    Then my PH jumped to 8.4 so I used thepoolcalculator and added 7 oz. It lowered to 7.8 I waited a week and had my husband add another 5oz because it was back up. I tested the next day and cya was 150 and my PH was still high 8.4.
    We are planning on draining it in the future to relocate because it is not on even ground and I thought I was going to have to drain it to lower the CYA anyways so I turned of the filter for about 4 days. It had been on 24 hours a day since set up until then. However it takes sometime and effort to level a back yard so my husband decided to test it again because he wanted to swim and cya was 50 but ph is still too high at 8.4. I do know how the CYA lowered itself. I may have misunderstood the overload of information I have read does CYA = Muriatic acid? or not? Also can I add more acid since its not supposed to evaporate I am afraid to over-saturate the water with acid. Is there another way to lower PH.
    Also my pools temp is never below 90. That is the average temp some days is 93 give or take a degree. Is this something I should worry about. I'm located in Texas so not sure what I can do about it.
    I have not Super-chlorinated my pool once. The tests seem good so far unless I am adding wrong I have no CC. TC and FC as of tonight are both 3. I have read that many people do this once every two weeks or so. Is this something I should be doing?

    Thanks in advance for your help!!
    16 ft X 16 ft x 4 ft round above ground pool. I believe its supposed to be about 5,000 gallons but is not on level ground.
    using AquaChek pool & spa 7 in 1 test strips. New vinyl pool purchase end of June 2015 (not sure if age matters for above ground vinyl)
    Thanks for your help!!

  2. Back To Top    #2

    Join Date
    Jun 2015
    Forest Hill

    Re: help with Ph levels and Muriatic acid

    Hi Happy Lil Lady,
    If I am correct, your CYA should not go up from muriatic acid. Muriatic acid is used to lower your pH. CYA stands for cyanuric acid and it is a chlorine stabilizer. It will help you maintain chlorine levels during the days sun. With your high temps, you should be good with your CYA at 50. You just need to make sure to maintain your FC at 6. You might want to look into performing the SLAM to get your pool in good shape. Also, getting a good test kit is highly recommended in this forum.
    I have added a few links here. Take your time reading them as there is a lot of info to digest. It all makes a load of sense after reading and doing everything.

    Pool School - SLAM - Shock Level And Maintain - How to SLAM your pool into good swimming shape.
    Pool School - Chlorine / CYA Chart - CYA to FC numbers. - The pool calculator. All kinds of usefulness right there!
    Pool School - Test Kits Compared - Find a good, reagent based test kit. They are somewhere between $40 - $60. Will save you a lot of money in the long run by providing more accurate results equating to less chemicals. Also, make sure to get one that has the FAS-DPD test included or add that onto your order. You will need it to read the shock level FC.

    Hope I was, in some way, helpful. Oh, and welcome to TroubleFreePools!
    Forest Hill, MD \ AG 24 FT Round ~ 13,000 Gal \ Hayward Power Flo LX 1.5HP w/ Hayward S210T Pro Series Sand Filter\ Perhaps 2009 \ Taylor Complete High K-2005 Test Kit \ Well filled

  3. Back To Top    #3

    Join Date
    Mar 2015
    Harvey, LA

    Re: help with Ph levels and Muriatic acid

    Yep, definitely need a good test kit to know if those numbers are right, we definitely don't trust a CYA test off a strip, much less the rest of the numbers...but as you probably know if you setup your pool info in poolmath, that TA is really high if you could assume it's accurate (we don't). The good news is Muriatic Acid lowers pH AND TA if it is right. I can't stress enough how important it is to have a good test kit, you really are driving blind without it.

    CYA = Cyanuric Acid, which is also called stabilizer in the pool stores and walmart/home depot. As was said before, Muriatic Acid will not affect CYA, though CYA will slightly affect pH in the same way that Muriatic Acid will (lowers pH). Muriatic Acid will diffuse into the water, and splashing around in the pool will raise pH again, so I wouldn't worry about it not leaving the pool because you'll likely be adding more later.

    Depending on the percentage bleach, you're adding anywhere from 9-21FC each time you add a if you are getting 12% bleach you are indeed bringing it up to shock level (unless you're buying from a pool store, the likelihood of you getting 12% is extremely low).

    So, get a test kit and post updated numbers, and we can help you get where you need to be!
    17.4k gallon IG pool with attached spa (spa itself is 730gal), Super Blue Diamondbrite plaster, Circupool SI-45+ SWG, BH/Hayward Cartridge Filter, 2hp 2speed Hayward Super II pump, , Jandy Valves, Waterway Skimmers, Rheem 400k Heater, Polaris 360 cleaner, built 2000+-, replastered June 2015, TF-100 kit---Here's my pool test reading history

  4. Back To Top    #4
    Mod Squad
    Join Date
    Aug 2012
    DFW, TX

    Re: help with Ph levels and Muriatic acid

    Welcome to TFP!

    It is important to maintain PH between 7.2 and 7.8. As you have seen high TA, over 120, will cause your PH to rise. Every time your PH gets to 7.8 add muriatic acid to lower it to 7.2. Doing this repeatedly will slowly lower your TA until PH and TA reach equilibrium. Pool School - Lower Total Alkalinity

    Start here, Pool School - ABCs of Pool Water Chemistry

    And +1 one on getting a good test kit. I use the TF100 from
    TFP Moderator
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    2012 build and pics, 20k gal gunite, black onyx pebblesheen, OK flagstone, IntellifoVS, cart filter w/Pleatco, IC40 SWG, Solartouch, 5 12'x4' solar panels, HP50HA heat pump, 8mil solar cover, borates, TF-100 test kit, SONOS, Doheny's Discovery Robot, hot tub on bleach

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