Misplaced Spa Calculations For Reducing Chlorine Using Hydrogen Peroxide

bxcrwlly

LifeTime Supporter
Dec 3, 2012
123
Central Florida
I seemed to have misplaced my once received from the forum, guidelines on how much Hydrogen Peroxide to use in my spa to reduce chlorine to a tolerable level around 3-5ppm. I did a bit of online research and found a few articles one of which talks about 2 ounces Hydrogen Peroxide for every 100 gallons of water and have also seen reference to a 1-1 ratio of Hydrogen Peroxide to PPM Chlorine. My spa is a round in ground unit and contains 243 gallons of water.

Any feedback from the forum is greatly appreciated. If I'm recalling correctly, it may have been ChemGeek who gave me an original formula, but just not sure.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
10,829
Northern NJ


 
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jimbethesda

Gold Supporter
Jul 2, 2018
238
Austin, TX
I seemed to have misplaced my once received from the forum, guidelines on how much Hydrogen Peroxide to use in my spa to reduce chlorine to a tolerable level around 3-5ppm. I did a bit of online research and found a few articles one of which talks about 2 ounces Hydrogen Peroxide for every 100 gallons of water and have also seen reference to a 1-1 ratio of Hydrogen Peroxide to PPM Chlorine. My spa is a round in ground unit and contains 243 gallons of water.

Any feedback from the forum is greatly appreciated. If I'm recalling correctly, it may have been ChemGeek who gave me an original formula, but just not sure.
What‘s your CYA level? As long as your chlorine is at or below shock level for your CYA, no need to reduce it. Is your chlorine the same level in your pool?
 

bxcrwlly

LifeTime Supporter
Dec 3, 2012
123
Central Florida
jimbethesda.....jim. Haven't checked CYA in a while....shame on me. Usually try to keep CYA between 70 & 80ppm. Chlorine in pool is/has been definitely below shock level. Came in as of 12/7/19 at 5ppm. I should've mentioned my spa has an overflow(spillover) to the pool which is on on at all times except when I'm in the spa, so the chlorine level in the spa would be the same as the pool except when spa is isolated. That's when the chlorine concentration jumps up because I'm dealing with 243 gallons of water isolated vs. 11,600 gallons when the pool and span are circulating.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
10,829
Northern NJ
Your ET should be able to reduce your IC20 % output when in SPA mode to not over chlorinate the smaller body of water.

How long fo you run the Spa? If the FC level in the spa starts the same as in the pool it should take a while for the spa FC to get excessive from the IC20 generation.

Can you put some numbers around the problem you are trying to solve?
 

bxcrwlly

LifeTime Supporter
Dec 3, 2012
123
Central Florida
IC20 reduces chlorine to isolated spa to 2%. Trying to solve when switching circulation from pool & spa to isolating spa, a formula to know how much hydrogen peroxide I need to add to spa. Spa is 243 gallons. Say as an example chlorine is 10ppm when I initially isolate. I’d want to reduce from 10 to at least 5ppm before getting in. I had a factor at one time that I could use to know that info. Trying to recreate formula.
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
11,668
Evans, Georgia
For some reason I recall using 1 ounce of Hydrogen Peroxide per 1ppm FC to reduce. I did this many years ago so I may be off, but this rings a bell to me. So like you want to reduce your FC from 5ppm to 3ppm, try 2 ounces of peroxide.

Or maybe it was 2 ounces for each ppm of FC???

Darn... it was a fairly simple method. Let us know if you try that and it works.

Maddie :flower: