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

Thread: Calculator or instructions for sodium thiosulfate?

  1. Back To Top    #1

    Calculator or instructions for sodium thiosulfate?

    Hello!

    I wanted to know if there is a calculator or instruction sheet y'all recommend for how much sodium thiosulfate to add in case my free chlorine gets out of whack again from over-zealous shocking. (it was as high as 65 before dumping in about 24 oz yesterday, dropped like a rock)

    I've looked all over the internet and am finding contradictory advice, anything from 0.5 oz to about 5 oz to decrease FC by 1 ppm for a 10,000 gallon pool.

    I was aiming for about 0.75 oz per 1 ppm decrease in my 2800 gallon pool as a conservative estimate.

    I am grateful for any suggestions!
    Intex 13' X 39" AGP, ~2800 gal filled, with Intex CS8110 SWG and Cu ion (now unplugged), Intex 635T pump/timer 1500 gph in a shady MD backyard.

  2. Back To Top    #2

    Join Date
    Nov 2010
    Location
    Calera, Al
    Posts
    271

    Re: Calculator or instructions for sodium thiosulfate?

    Have you checked on the use of hydrogen peroxide? From what I have read, hydrogen peroxide neutralizing chlorine is supposed to be linear. 2.6 oz of 27% to neutralize 1 ppm of FC in 10,000 gallons.
    17,000 gal, IG Gunite Diamond Brite plaster Kidneybean,w/7x11 tanning ledge& 3x5 swimout bench,244T 300lb Hayward Pro high rate sand filter(63 GPM) , Hayward 1Hp Super Pump w/3/4 hp booster pump, Polaris 280, Laars Lite 2 175k N/G Heater, Tf-100, Speed stir

  3. Back To Top    #3

    Re: Calculator or instructions for sodium thiosulfate?

    I can't find much for hydrogen peroxide except for usage in fish tanks and for industrial (read: city water) systems.

    Also doesn't it depend on what kind of pool system you have (baquacil or chlorine), and how much would you need? Could drug store (3% in solution, I think) version work in a pinch when the pool store is closed or out of stock?

    Stuff all over the internet about the usage of both but I can't find a set of hard numbers specifically for pool use.
    Intex 13' X 39" AGP, ~2800 gal filled, with Intex CS8110 SWG and Cu ion (now unplugged), Intex 635T pump/timer 1500 gph in a shady MD backyard.

  4. Back To Top    #4

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

    Re: Calculator or instructions for sodium thiosulfate?

    In the thread Best way to reduce chlorine level, I gave the following amounts to lower 1 ppm FC in 10,000 gallons:

    2.6 ounces weight of sodium thiosulfate
    1.5 ounces weight of sodium metabisulfite (some claim up to 3 ounces is needed)
    2.4 ounces weight of sodium sulfite
    2.6 cups of 3% hydrogen peroxide (2.3 fluid ounces of 27% hydrogen peroxide)
    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"

  5. Back To Top    #5

    Re: Calculator or instructions for sodium thiosulfate?

    Thanks, this list is fantastic! I am very grateful, because I now have options in case things go awry again!

    I think one of my HTH stabilizers (CYA) contains sodium sulfite as well. Should I avoid using it and only use the "plain" stabilizer?
    Intex 13' X 39" AGP, ~2800 gal filled, with Intex CS8110 SWG and Cu ion (now unplugged), Intex 635T pump/timer 1500 gph in a shady MD backyard.

  6. Back To Top    #6

    Re: Calculator or instructions for sodium thiosulfate?

    I don't think that any cyanuric acid made for pools contains sodium sulfite. Can you double check the ingredients?

  7. Back To Top    #7
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: Calculator or instructions for sodium thiosulfate?

    You know, rather than spending a lot of time trying to figure out how to use sodium thiosulfate, you would be much better off trying to figure out how to never need to use sodium thiosulfate again. FC levels go down on their own, so normally you can just wait it out. Getting the FC level wildly too high can damage the pool and is best avoided altogether.
    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

  8. Back To Top    #8

    Join Date
    Jul 2012
    Location
    Dumfries & Galloway, Scotland
    Posts
    296

    Re: Calculator or instructions for sodium thiosulfate?

    JasonLion makes an excellent point. I have 100g per 10,000 imp gallons for a 1ppm reduction which would (very) roughly be 1/4lb per 10,000 US Gallon for 1ppm in your money, but it would be important to check the instructions as no doubt a store bought chlorine reducer would not be as strong. When using Sodium Thiosulphate it is important not to overshoot, as it can and will strip every residual of Free Chlorine from your pool if overused.
    Stuart Murray
    Scotland UK
    UK NPPOC

Posting Permissions

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