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Thread: Should I add chemicals one at a time?

  1. Back To Top    #1

    Join Date
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    Should I add chemicals one at a time?

    I'm fighting an algae outbreak. My pool had looked wonderful up until 1 week ago. The water was crystal clear with no visible signs of algae. Then we started getting unusually large amounts of rain and everything has rapidly gone down hill.

    I've been throwing massive amounts of bleach into the pool (using the pool calculator) and testing it daily. I'm trying to get my FC to 20 and to hold it there until the algae starts to disappear but no luck yet. We're also brushing the pool twice daily to loosen the algae.

    On Monday I tested the water with the following results:
    FC: 0
    PH: 8.2
    TA: 160
    CH: 240
    CYA: 30


    I added chemicals Monday evening and retested on Tuesday and the numbers were:
    FC: 5
    PH: 7.5
    TA: 120
    CH: 260
    CYA: 50

    I added more bleach on Tuesday evening. I didn't do anything yesterday due to heavy rain.

    This morning I retested and the numbers are:
    FC: 0
    PH: 8.2
    TA: 180
    CH: 200
    CYA: 35

    The numbers are jumping all over the place.

    When I added all of the chemicals on Monday the pool walls got even greener even though the water remained clear. By this morning there is still considerable algae but the majority of it has disappeared.

    I should add that since Monday we've had over 9 inches of rain so I'm constantly having to drain some of the excess water. What's more we are scheduled to get heavy rain for the next 5 days.

    My main question is how to add the chemicals. Do I add all of them at once or should I space them out over a period of time i.e. hours or days? I've been adding them simultaneously since -based on my understanding - if the chemistry is off in one category it will affect how the well the other chemicals work. However, after adding everything at once the pool looks worse for the next 24-36 hours.

    Right now I feel like my dog chasing his tail. Any suggestions are greatly appreciated.

    With this much rain and the algae problem someone suggested dropping several chlorine tabs directly into my skimmer. Your thoughts?
    15,400 gal with attached spa, IG concrete, FNS 60# DE, 2HP Pump, Gas Heater 400 BTU , 1.5HP Booster Pump, Polaris 360, Nature 2 (never use)

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    dmanb2b's Avatar
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    Re: Should I add chemicals one at a time?

    Hey Barney...how are you you testing your water? TF100, Taylor K2006 or Pool Store?

    If all you are adding is chlorine, your TA and PH shouldn't be jumping around so much. If your PH is 8.2, you should reduce it to 7.4.

    30 minutes after you adjust your PH you can start adding Chlorine and enough of it to raise it to shock level and keep it there until you are done shocking. It sound like you are not adding enough chlorine to obtain shock level.
    24'x52" AGP (13,500 Gallons), Intex SWG, (2)Solar Bear 4x20 panels, Hayward S220T Filter, 1/2hp Pentair Superflo

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  3. Back To Top    #3

    Re: Should I add chemicals one at a time?

    Wow... 9 inches of rain is insane.

    Keep in mind that the pH of normal rain is about 5.7, and it has a very low TA.

    In addition, depending on your setup (e.g. covered vs. uncovered) you would be getting a heck of a lot of aeration.

    With rain that heavy, your test results may not be showing a consistant mixture of rain water vs. pool water. And there could be contamination of your test samples with rain water.

    If it were me, I would wait for the rains to subside before taking any further action. Maybe some acid to get the pH down. And, it wouldn't hurt to keep your FC up. I would aim for just making the water a little better... not shooting for any particular numbers.

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    Mod Squad Bama Rambler's Avatar
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    Re: Should I add chemicals one at a time?

    To directly answer your topic question. Yes you should add chems one at a time except for CYA. You can hang it in a sock while adding other chems.

    Now a couple things I noticed in your post.

    Testing and adding once a day is going to take a long time to kill off the algae. You should be doing it as much as once an hour to begin with if possible.

    You should bring your pH down to about 7.0 and then raise your FC up to shock level and hold it there.

    The rain won't make a huge difference unless you get a ginormous amount all in one day. An inch a day or so won't make a big difference.

    And lastly, do you have any reason to suspect metals in your water?
    Dave J. TFP Moderator
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    Re: Should I add chemicals one at a time?

    Quote Originally Posted by dmanb2b
    Hey Barney...how are you you testing your water? TF100, Taylor K2006 or Pool Store?

    If all you are adding is chlorine, your TA and PH shouldn't be jumping around so much. If your PH is 8.2, you should reduce it to 7.4.

    30 minutes after you adjust your PH you can start adding Chlorine and enough of it to raise it to shock level and keep it there until you are done shocking. It sound like you are not adding enough chlorine to obtain shock level.
    I'm using the TF100. I think I will concentrate on the PH and follow with chlorine until some of this rain settles down.
    15,400 gal with attached spa, IG concrete, FNS 60# DE, 2HP Pump, Gas Heater 400 BTU , 1.5HP Booster Pump, Polaris 360, Nature 2 (never use)

  6. Back To Top    #6

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    Re: Should I add chemicals one at a time?

    Quote Originally Posted by Bama Rambler
    To directly answer your topic question. Yes you should add chems one at a time except for CYA. You can hang it in a sock while adding other chems.

    Now a couple things I noticed in your post.

    Testing and adding once a day is going to take a long time to kill off the algae. You should be doing it as much as once an hour to begin with if possible.

    You should bring your pH down to about 7.0 and then raise your FC up to shock level and hold it there.

    The rain won't make a huge difference unless you get a ginormous amount all in one day. An inch a day or so won't make a big difference.

    And lastly, do you have any reason to suspect metals in your water?
    I don't believe I have any metals. We're got 3 inches of rain within 2 hrs on Monday and a daily total of 4, Tuesday we got 3 inches for the day and yesterday a 1 hour downpour gave us 2 inches.

    I've been adding chlorine throughout the day (except yesterday) and have put as much as 415 oz of bleach in at one time. The calculator says I need another 415 oz so I'll put that in now and see what I need at the end of the day.
    15,400 gal with attached spa, IG concrete, FNS 60# DE, 2HP Pump, Gas Heater 400 BTU , 1.5HP Booster Pump, Polaris 360, Nature 2 (never use)

  7. Back To Top    #7

    Re: Should I add chemicals one at a time?

    Just keep in mind that at high pH's, such as yours, the effectiveness of chlorine drops. If your pH reading is accurate, you are probably only getting about 25% effectiveness of your chlorine (vs. 50% at standard pH levels).

    That said, I do not know if I would spend TOO much time chasing your pH in the conditions you are describing. And, maybe I am over-exagerating your conditions... I am kinda imagining someone trying to balance their water during a hurricane.

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