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Thread: Updates and new question about sequestering agent

  1. Back To Top    #1

    Updates and new question about sequestering agent

    Guys still shocking the pool using bleach and did the D.E. addition to my sand filter. I'm thinking my sand probably needs replaced because it took four cups of D.E. to raise my PSI by 1. But, it may be my imagination, however the water from the return actually seems visibly clearer as it comes through. I've got some serious bleach going now trying to crank my FC up to about 16 and burn off the CC and kill any additional algae of whatever kind. Did a backwash this morning and water was as brown as mud (good sign in my mind). Everything seems to be going okay, but....
    as the water is clearing I am noticing a brown stain on my liner/steps again. I did the ascorbic acid treatment about a month ago and liner, etc. was all clear as bell afterward. My PH is currently pretty low and I had planned to keep it that way through the shock in order to insure I didn't get the iron/metal stain again. However, I fear it is showing up a bit and possibly was deposited even before I did the shock itself. My latest question is:
    Can I add sequestering agent with my FC up this high and it still be effective? Or will the high FC react with the sequestering agent and "burn it off" so to speak?

    Thanks for the info. Hear are my current numbers before adding four additional 182 oz bottles of bleach this afternoon. I have an inground vinyl liner with estimated capacity of 22000-25000 gallons with a sand filter (with D.E. addition added earlier today). Planning on doing an aeration/acid deal to lower TA in the next few weeks, btw.

    Numbers before the four bottles:
    (From Drop Test)
    FC 4.0
    CC 5.0
    PH 7.1
    TA 230

    (From Test Strips [I know, I know, they are virtually worthless, but all I have at the moment to do CYA)
    Total Hardness 150
    CYA ~30

    Thanks for the help and help already given.

  2. Back To Top    #2

    Join Date
    May 2007
    Location
    South Central NJ
    Posts
    3,192

    Re: Updates and new question about sequestering agent

    Well, you've already killed everything. Get the pH up so you can oxidize better.

    Sequestering agents will be broken down by the high chlorine fairly quickly. Wait until you can run at a lower FC level.

    The size of the filter and pump size determine how much DE is right.

    Are you on a well for your fill water?

    Scott
    Owner of - PoolGuyNJ LLC
    Expert Pool and Spa Repairs, Renovations, and Augmentation. Helping people decide what is the right gear for meeting their needs. Expectations Set, Expectations Met, No Surprises.

  3. Back To Top    #3

    Re: Updates and new question about sequestering agent

    I am off off a municipal system which comes from a well.

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    Join Date
    May 2007
    Location
    South Central NJ
    Posts
    3,192

    Re: Updates and new question about sequestering agent

    Verify the fill water first. Check for iron and copper too, the two main metals that are sometimes found in fill water.

    It can take quite a bit of time to clear the cloudiness.

    Scott
    Owner of - PoolGuyNJ LLC
    Expert Pool and Spa Repairs, Renovations, and Augmentation. Helping people decide what is the right gear for meeting their needs. Expectations Set, Expectations Met, No Surprises.

  5. Back To Top    #5
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: Updates and new question about sequestering agent

    It really depends on the sequestrant. Most of the better sequestrants are fine with higher FC levels, while some of the less good kinds will be broken down right away. Also, if you have been having staining problems you should certainly not raise the PH.
    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

  6. Back To Top    #6

    Paying my stupid tax and abscorbic acid

    Okay so maybe I screwed up (well I know I did). As a recap, I had done the abscorbic acid deal to remove stains shortly after opening and had great success for 3-4 weeks. However, I was out of town and we had a few storms so the chlorine got a little low and we had an algae bloom. Brought the pool up to shock levels to get rid of the algae and get my CC down, but apparently left my Ph a little too high so the water cleared of everything and the stain reappeared. These were the numbers from my previous post, right before adding some additional bleach to get up to shock levels:
    Numbers before the four bottles:
    (From Drop Test)
    FC 4.0
    CC 5.0
    PH 7.1
    TA 230

    (From Test Strips [I know, I know, they are virtually worthless, but all I have at the moment to do CYA)
    Total Hardness 150
    CYA ~30

    Afterwards, the pool began to clear as the FC levels were off the chart. The I decided after running a week or so to let my chlorine gradually go down over a few days and do the abscorbic acid thing again. I did had So I raised my ph up too high (exactly what you were warning against) and the stain reappeared. The shock did burn everything off including killing the algae and lowering the combined chlorine, but the Ph was still too high for my situation (lots of metals). I added sequestering agent, but did so when my FC was still at shock level which apparently burned it off. Stain was really, really bad again.

    So here's what I did today, since my water was now crystal, I let my chlorine dwindle down over a couple of days and today did the ascorbic acid deal again which removed the stain. Here are my current numbers after the acid treatment:
    A few hours after treatment with stain totally gone:
    (From Drop Test)
    FC 0.0
    CC 0.0
    PH <6.8
    TA 180

    (From Test Strips [I know, I know, they are virtually worthless, but all I have at the moment to do CYA)
    Total Hardness 150
    CYA ~30

    Now, I went ahead and installed a little aerator fountain with the thoughts it would raise my Ph gradually without adding to my already slightly high TA (still high but now down to 180 after the abscorbic acid). The aerator is currently going, the pool is clear, the liner is blue, and everything is clicking along.

    NOW FOR THE QUESTIONS (unless you want to offer input on some of the stuff listed above):

    (1) How should I proceed in regards to chlorine? I mean should I let the aerator do its thing and slowly raise the chlorine level using bleach and/or trichlor tabs (convenient and might help my CYA which was still low). If so at what rate?

    (2) Regarding PH, should I just let the aerator do it's thing, its just a fountain on one of my returns? Should I add any Borax at this point to raise it (I didn't think so considering slower is better at preventing metal stains from reappearing and my TA is still substantial.

    (3) Should I go ahead and add some algaecide while I play this game with chlorine? I know it isn't "polyquat," but the closest thing available in town is from Walmart:
    Aqua Chem. Algaecide 50%.
    Ingredients: Allkyl (c-67% C, 25% C, 7% C, 1%).
    dimethyl benzyl ammonium chloride 50.0%.
    Other ingredients 50.0%.
    Total 100.0%.
    Should I use this?

    (4) Do you think the pool is safe for the kids to swim in right now in its present condition?

    By the way my pool is around 25,000 gallons and comes from a municipal well system.

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