Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 11 of 11

Thread: Sodium Hypochlorite

  1. Back To Top    #1
    meatloaf's Avatar
    Join Date
    Feb 2008
    Location
    Gilbert AZ
    Posts
    373

    Sodium Hypochlorite

    Is Sodium Hypochlorite 10% the same as 10% bleach?
    Thanks
    My pool is a 10,500 gallon (420 Sq Ft ) kidney shape. A hand made sheer decent waterfeature. STA-RITE HRPB30, Sand filter 30" 98 GPM,
    1 HP Maxi-Glas 2 pump, BBB Method, Taylor K-2005 test kit, 50 Watt 12V low-voltage pond light illuminates the pool at night for a nice soft glow.
    250 gallon stand-alone hot tub. Got it FREE!

  2. Back To Top    #2

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Location
    Sebring, Florida
    Posts
    30,077

    Re: Sodium Hypochlorite

    Yes.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  3. Back To Top    #3
    meatloaf's Avatar
    Join Date
    Feb 2008
    Location
    Gilbert AZ
    Posts
    373

    Re: Sodium Hypochlorite

    Thanks, I thought it was but I wanted to check with the experts.
    My pool is a 10,500 gallon (420 Sq Ft ) kidney shape. A hand made sheer decent waterfeature. STA-RITE HRPB30, Sand filter 30" 98 GPM,
    1 HP Maxi-Glas 2 pump, BBB Method, Taylor K-2005 test kit, 50 Watt 12V low-voltage pond light illuminates the pool at night for a nice soft glow.
    250 gallon stand-alone hot tub. Got it FREE!

  4. Back To Top    #4
    Kes's Avatar
    Join Date
    Apr 2010
    Location
    Worcester UK
    Posts
    46

    Re: Sodium Hypochlorite

    It depends what you mean by the same. As far as I can tell the Sodium Hypochlorite constituent of both is the same. However, I'm no expert, so I'll cut and paste what Chem Geek posted.

    '6% Bleach is, by weight, 6.0% sodium hypochlorite (i.e. chlorine), 4.7% salt, and 89.3% water. All sources of chlorine will add salt to the pool as chlorine turns into chloride (salt) when it gets used up, but bleach adds salt upon addition as well.'

    and...

    'For every 10 ppm FC added by ANY source of chlorine, it will result in 8.2 ppm salt from the consumed chlorine that turns into chloride salt. With bleach, chlorinating liquid, and lithium hypochlorite, there is an additional 8.2 ppm salt upon addition so the net total result is 16.5 ppm.'

    So I interpret that as you would get additional salt from using bleach instead of sodium hypochlorite. Why additional salt is added to bleach I don't know, and CG didn't say. (Perhaps he will here, and correct my chemistry.)
    11,000 Imp galls inground hopper 15' x 35', Delifol liner (vinyl), sand filter, Abrisud Classic cover, Palintest 315C test kit

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

    Re: Sodium Hypochlorite

    Household bleach and sodium hypochlorite sold for pool use are both produced by the same companies in the same plants in the same way. Bleach/sodium hypochlorite is produced by running electricity through salt water in a process very similar to what happens inside a SWG, but on a much larger scale. The "extra" salt is required for the production process to work correctly.
    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

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

    Re: Sodium Hypochlorite

    Quote Originally Posted by Kes
    Why additional salt is added to bleach I don't know, and CG didn't say. (Perhaps he will here, and correct my chemistry.)
    As Jason noted, the manufacturing process of making bleach or chlorinating liquid, all of which are "sodium hypochlorite", has salt created in the product by the way it is made. It isn't added intentionally. Essentially, the electrolysis of brine water produces chlorine gas and this then gets added to a solution of lye (sodium hydroxide). The chemical reaction that occurs produces salt:

    Cl2(g) + 2NaOH ---> NaOCl + NaCl + H2O
    Chlorine Gas + Lye ---> Sodium Hypochlorite + Salt + Water

    Essentially, half of the chlorine gas goes to making hypochlorite and the other half goes to making salt. Unfortunately, there is no easy or inexpensive way to make hypochlorite without the salt.
    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"

  7. Back To Top    #7

    Join Date
    Jul 2010
    Location
    Gonzales, LA
    Posts
    20

    Re: Sodium Hypochlorite

    In case anyone is interested the chlorine, sodium hydroxide (caustic) and hydrogen are all produced at the same time in the same cell. Caustic comes out the bottom as a liquid, chlorine and hydrogen come out the top as a gas but they are seperate. The hydrogen and sodium hydroxide are produced on the same side of the cell and the chlorine is on the oppisite. We do it by adding salt water to a cell and running 150 thousand amps through it that break it into the three different chemicals.

    We also make bleach (sodium hypochlorite) by circulating sodium hydroxide (caustic) in a tower and running chlorine through it. It is really strong but unfortunantely I can't use it because it is not very clean.

    Pretty much what ChemGeek said but just a little extra useless info LOL !!!

    CHEM GEEK
    One thing I have always wondered is does a SWG add pH to the pool. In other words to produce the chlorine you release the Cl's, so what happens to the Na's. Do they join with OH's and form a little sodium hydroxide?
    17,000 gal. AG with Pentair Clean and Clear 100 cartridge filter and 1 1/2 hp pump at about 55 GPM.

  8. Back To Top    #8

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

    Re: Sodium Hypochlorite

    I was only giving the chlorine gas and bleach production side of the chlor-alkali process that you describe (a very simplified description of different chlor-alkali methods is here).

    As for what happens in an SWG, this post describes how the production of chlorine in an SWG is essentially identical to adding a hypochlorite source of chlorine so is pH neutral when accounting for chlorine consumption/usage. However, in practice we find that the pH rises in most SWG pools. There are probably two reasons for this. First is that the increased aeration from the hydrogen gas bubbles increases the outgassing of carbon dioxide. Lowering the Total Alkalinity (TA) helps to reduce this effect, but doesn't usually completely eliminate the pH rise. I'm not sure about the other source of pH rise, but it may be undissolved chlorine gas outgassing as that would definitely have the pH rise. Shorter pipe runs from the SWG to the pool would have more of this effect. Lowering the SWG on-time by having a higher CYA level to lower chlorine demand and using 50 ppm Borates to inhibit algae growth and possibly lower chlorine demand can also help (the borates are also an additional pH buffer that help reduce scaling in SWG cells).

    The sodium ions are irrelevant to the SWG chlorine production, just as they are in the chlor-alkali process. They are only there for charge balance and as ions for conductivity, but they do not directly participate in any of the electrochemistry.
    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"

  9. Back To Top    #9

    Join Date
    Jul 2010
    Location
    Gonzales, LA
    Posts
    20

    Re: Sodium Hypochlorite

    I know you were giving the simplified version, but I just had to act like I know something. LOL !!! I just wrote that post cause most people I explain that to find it quite interesting how you get those three products from salt water.

    Thanks for the post. I think I understand about the SWG. I am not real good with chemistry just the little I know from work. But one thing you said caught my attention, and please don't think I am arguing,just learning, but you mentioned that the sodium Ion is irrelevent in the chlor-alkali process. But without it how would you get the sodium hydroxide. Is it that the -OH ion is all you need and the Na is just a by product. If the answer is way to deep for me then just tell me. Dont want to waste your time Thanks again!!!
    17,000 gal. AG with Pentair Clean and Clear 100 cartridge filter and 1 1/2 hp pump at about 55 GPM.

  10. Back To Top    #10

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

    Re: Sodium Hypochlorite

    What I meant was that the sodium ion had little to do with the electrolysis itself. It wasn't "created" or transformed by the electrolysis. What is produced is actually hydroxide ions in water. It's only when the water is removed that you can get solid sodium hydroxide. The sodium was there all along from the salt (though more migrates from the chlorine gas generation side to the hydrogen gas generation side to keep charge balance). The hydroxide ions, on the other hand, come from electrolysis of water that also produced hydrogen gas.
    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"

  11. Back To Top    #11

    Join Date
    Jul 2010
    Location
    Gonzales, LA
    Posts
    20

    Re: Sodium Hypochlorite

    Got cha! I miss understood what you were saying. Thanks !!!!
    17,000 gal. AG with Pentair Clean and Clear 100 cartridge filter and 1 1/2 hp pump at about 55 GPM.

Posting Permissions

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