Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 8 of 8

Thread: after routine spa water change, do I need to SLAM

  1. Back To Top    #1

    Join Date
    Oct 2014
    Location
    Seattle, WA
    Posts
    47

    Question after routine spa water change, do I need to SLAM

    Hit the 4 month mark on my chlorine based spa after conversion from Baquacil - using the methods from TFP with great success. I was having only a 20-25% over night FC loss at 98-100F, great water clarity, no foaming. Decided to go ahead and change the water in spite of it being in great condition b/c I had the time, needed to replace the weir and now have some Ahh-some. Did 2 treatments with minimal, then almost no gunk on the second round. Finished out by emptying, wiping down, rinsing, emptying as much as possible, then refilling.

    After adding my calcium, baking soda, leftover Gentle Spa and muriatic acid per PM, then finally bleach I have the following:
    CH is 140
    TA 50
    pH 7.2
    Borates 30-50
    FC 10.5 and CC 0
    CYA was added to attain 30, but I won't test the level for another 10-14 days.
    I'm also going to wait on retesting the Borate for a few days before making any further adjustments.

    Two questions:
    1: do I have to SLAM now? If I understood some earlier threads, SLAMing doesn't hold for spas.....should I just see if I'm 20-25% or less in my over night FC loss and call it good?
    2: did I need to shock after the refill... I shocked cause I thought it was what I was supposed to do, but now what? Could I have just added enough bleach to get to 5-6 and stopped there? instead of the shock level of 10 (assume zero dissolved CYA)? I haven't been shocking at all the last 4 months......just using maintenance 3.5oz 8.25% bleach per 1 person hr, dropping the temp when OOT, and testing and using PM when needed.

    Water is sparkly beautiful!
    3150 gallon (8'x14'x3.75') vinyl lined Original Endless Pool opened 10/10/2014 - chlorine based with UV sanitizer, 50 SF filter cartridge, AG outdoors with opaque retractable cover, Gecko controller In.ex 4 Kw heater, 88 F, triple insulated; Sundance Altamar 390 gallon spa opened July 2000; chlorine based conversion from Baqua Oct 2014; outdoors, on deck, covered, 98F, no ozonator/sanitizer, 125 SF filter cartridge. FAS-DPD chlorine testing.

  2. Back To Top    #2

    Join Date
    Mar 2007
    Location
    San Rafael, CA USA
    Posts
    12,082

    Re: after routine spa water change, do I need to SLAM

    You don't need to SLAM. Just see if your 24-hour loss is good (it's not overnight since spas are covered and not exposed to sunlight). The 25% loss (or less) would be with no ozonator. With an ozonator the loss is higher because ozone reacts with chlorine.

    You should not need to shock your spa. You don't need to do that in a pool either. If you properly maintain the chlorine level that the spa will be in good shape. You do need to add enough chlorine after each soak to oxidize the bather waste. You shouldn't need to use MPS (potassium monopersulfate -- I presume that's what you meant by PM) with a proper chlorine regimen though if you already have some and want to use it to oxidize some of the bather waste you can.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

  3. Back To Top    #3

    Join Date
    Oct 2014
    Location
    Seattle, WA
    Posts
    47

    Re: after routine spa water change, do I need to SLAM

    PM, Pool Math. Sorry.
    3150 gallon (8'x14'x3.75') vinyl lined Original Endless Pool opened 10/10/2014 - chlorine based with UV sanitizer, 50 SF filter cartridge, AG outdoors with opaque retractable cover, Gecko controller In.ex 4 Kw heater, 88 F, triple insulated; Sundance Altamar 390 gallon spa opened July 2000; chlorine based conversion from Baqua Oct 2014; outdoors, on deck, covered, 98F, no ozonator/sanitizer, 125 SF filter cartridge. FAS-DPD chlorine testing.

  4. Back To Top    #4

    Join Date
    Oct 2014
    Location
    Seattle, WA
    Posts
    47

    Re: after routine spa water change, do I need to SLAM

    So. No need to SLAM or shock, just go back to prior routine .
    3150 gallon (8'x14'x3.75') vinyl lined Original Endless Pool opened 10/10/2014 - chlorine based with UV sanitizer, 50 SF filter cartridge, AG outdoors with opaque retractable cover, Gecko controller In.ex 4 Kw heater, 88 F, triple insulated; Sundance Altamar 390 gallon spa opened July 2000; chlorine based conversion from Baqua Oct 2014; outdoors, on deck, covered, 98F, no ozonator/sanitizer, 125 SF filter cartridge. FAS-DPD chlorine testing.

  5. Back To Top    #5

    Join Date
    Mar 2007
    Location
    San Rafael, CA USA
    Posts
    12,082

    Re: after routine spa water change, do I need to SLAM

    Yup.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

  6. Back To Top    #6

    Join Date
    Oct 2014
    Location
    Seattle, WA
    Posts
    47

    Re: after routine spa water change, do I need to SLAM

    Just to be complete, my next am FC was 9.5, CC 0.
    Perfect. Love this site.
    3150 gallon (8'x14'x3.75') vinyl lined Original Endless Pool opened 10/10/2014 - chlorine based with UV sanitizer, 50 SF filter cartridge, AG outdoors with opaque retractable cover, Gecko controller In.ex 4 Kw heater, 88 F, triple insulated; Sundance Altamar 390 gallon spa opened July 2000; chlorine based conversion from Baqua Oct 2014; outdoors, on deck, covered, 98F, no ozonator/sanitizer, 125 SF filter cartridge. FAS-DPD chlorine testing.

  7. Back To Top    #7

    Re: after routine spa water change, do I need to SLAM

    Quote Originally Posted by chem geek View Post
    You don't need to SLAM. Just see if your 24-hour loss is good (it's not overnight since spas are covered and not exposed to sunlight). The 25% loss (or less) would be with no ozonator. With an ozonator the loss is higher because ozone reacts with chlorine.

    You should not need to shock your spa. You don't need to do that in a pool either. If you properly maintain the chlorine level that the spa will be in good shape. You do need to add enough chlorine after each soak to oxidize the bather waste. You shouldn't need to use MPS (potassium monopersulfate -- I presume that's what you meant by PM) with a proper chlorine regimen though if you already have some and want to use it to oxidize some of the bather waste you can.

    Thank you very much, thats exactly the kind of help and advice im looking for.

  8. Back To Top    #8
    Patrick_B's Avatar
    Join Date
    Jun 2011
    Location
    Midland TX
    Posts
    15,001

    Re: after routine spa water change, do I need to SLAM

    Quote Originally Posted by windowslasvegas369 View Post
    Thank you very much, thats exactly the kind of help and advice im looking for.
    Welcome to the forum!

    Glad you found what you needed. I hope you join in and enjoy your time here.
    TFP Moderator
    Essential Links:
    ABC's Of Pool Chemistry, Test Kits, SLAM Your Pool
    28K Gal IG FreeForm, CLI Quartz, Pentair 36"SF & VS Pump, Dolphin M5, Rheem

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •