+ Reply to Thread
Results 1 to 3 of 3

Thread: Question for the chemists

  1. #1
    Join Date
    Jul 2011
    Location
    Southern Maine
    Posts
    8

    Question Question for the chemists

    My G25 Nature 2 cartridges hit $120 this year so I started searching for:
    1. Cheaper cartridges.
    2. Proof that it is worth the money.
    Whilst searching for the proof, I discovered the BBB method and started researching that.
    Across several forums, I got conflicting information about superchlorination and Potassium Monopersulfate.
    Some say one or the other gets rid of the organic but not the inorganic and vice versa.
    Some say using Potassium Monopersulfate creates nitrates which feeds the algae.

    But I can find no chemical reaction diagram of what happens to combined chlorine when hit with either method to see what remains after the reaction.

    Does anyone know?

    The curiosity hit after the accusation of Potassium Monopersulfate and algae as I started using it 3 years ago and the bottom of the pool and a spot on the side wall is black ... but no scrubbing gets it off the vinyl. I had attributed it to the black underside of the winter cover which had disintegrated over the years, but the pool guy thinks it is black algae growing through the vinyl from the ground water.

    Lack of info REALLY drives me crazy .... like a splinter in the brain.
    ~18,000g; 16' x 32' IG; Vinyl; 1HP x 36sq-ft Hayward DE; Solar Attic PCS2 Heat; G25 Nature2; New Water 400; Fiber Stars 8-Color Perimeter and Wall; Clear Cover

  2. #2
    PoolDoc's Avatar
    PoolDoc is offline Administrator Quark Inspector PoolDoc 5 stars PoolDoc 5 stars PoolDoc 5 stars PoolDoc 5 stars PoolDoc 5 stars PoolDoc 5 stars PoolDoc 5 stars
    Join Date
    Jan 2005
    Location
    Georgia
    Posts
    11,386

    Default Re: Question for the chemists

    Chem_Geek has posted extensively about this topic, for example HERE, in this exchange between him and a chemical gizmo salesman from Cyprus, and again HERE on an exchange regarding use of monopersulate with Nature2.

    Those posts are other sites -- Chem_Geek posts on ALL the pool sites -- and there are some posts in the China Shop here, but they are not as extensive.

    Of course, if you want to skip to the the bottom line, here is is: Nature2 doesn't really work, and MPS is a waste of money.

    PoolDoc

  3. #3
    chem geek is offline PF Supporter Whibble Konker chem geek 4 stars chem geek 4 stars chem geek 4 stars chem geek 4 stars
    Join Date
    Nov 2004
    Location
    California
    Age
    64
    Posts
    2,226

    Default Re: Question for the chemists

    Both chlorine and MPS are selective oxidizers. That means they don't oxidize everything and they are somewhat different in what they oxidize and how long it takes. It is an oversimplification to say that one oxidizes inorganics while the other oxidizes organics.

    When it comes to inorganics, this is really ammonia in sweat and urine. Both chlorine and MPS will oxidize ammonia mostly to nitrogen gas, but according to this paper, MPS reacts slowly with ammonia and instead in the presence of chloride salt its sulfate radicals forms chlorine that then oxidizes the ammonia. With chlorine, about 10% of the ammonia will become nitrate (that reaction is shown in one of my posts in this link). I don't know the amount that becomes nitrate when using MPS but it is probably similar. As far as nitrates and phosphates which are nutrients for algae, that is irrelevant since one can maintain a chlorine level in a pool that prevents algae growth regardless of nutrient level. Algae is limited in growth rate by sunlight and temperature so even if you dumped fertilizer in the pool you would still be able to control algae with chlorine alone.

    As for organics, neither chlorine nor MPS oxidize urea quickly though chlorine in an outdoor pool breaks down from the UV in sunlight to produce hydroxyl free radicals that may keep urea in check. Chlorine's primary reaction with organics is that of substitution on some nitrogen sites producing Combined Chlorine (CC). MPS does not directly produce combined chlorine and will often oxidize compounds that would otherwise form CC. That is the main advantage of using MPS -- that it does not form chlorinated disinfection by-products.

    The copper ions in Nature2 can prevent algae growth and kill existing algae if the concentration is high enough, but that concentration of copper ions is high enough to create stains and to turn blond hair green unless you keep the pH rather low (7.4 or lower at ALL times). If copper ions didn't have these side effects, then they would be a great product, but you can't hope or wish for the perfect product if in reality it does not exist. Chlorine is about as close as one gets since it is both a disinfectant and an oxidizer and with Cyanuric Acid (CYA) can be at very low active levels while still being effective.

    The combination of Nature2 and MPS in spas, where the Nature2 in this case is silver and zinc ions, IS a reasonable alternative disinfection system that actually passes EPA DIS/TSS-12, but ONLY for spas since it requires hot spa temperatures to be able to kill bacteria quickly enough. Even so, most people find that they still need to use chlorine once every week or two to keep the water clear. However, for pools, as Ben wrote, Nature2 with MPS doesn't work well and is an expensive waste of money.
    Last edited by chem geek; 07-08-2011 at 02:10 AM.

+ Reply to Thread

Similar Threads

  1. Spring Vacuum Question and Liner Question
    By DougM in forum Pool Startup, Shutdown, & Winter Operation
    Replies: 6
    Last Post: 05-21-2011, 11:11 PM

Bookmarks

Posting Permissions

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