Hydrolysis As A "sanitizer" ... Real Or "snake Oil"?

[Dark Helmet]

A family member mailed me a link to the Natural Water Environments home page and asked me whether I'd heard of this system and whether we should check it out:

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Natural Water Environments (home page)
* NOGSYS Hydrolysis Technology (light on details)
* NOGSYS - Nascent Oxygen Generating System (picture)
* NOGSYS Residential Use
* Hydroxyl Radical Generating System (HRGS) Green Hotel

I'm far from a guru (just a residential pool owner) so I thought I'd ask here. I figured surely someone here has already browsed this site. So is there something worthwhile here or just snake oil?

I do know enough to see that they intentionally "muddy the water" a lot, trying to entice pool owners that don't really know anything about the underlying water chemistry into buying their system, so I'm defensively inclined to suspect snake oil. For instance they're decrying the "nasty chemicals" folks put in their pool, touting this as the reason their pool "sanitizer" is the solution. However:

1. They say you still have to keep "minimum levels of chlorine or bromine" in the pool along side this solution, so we haven't done away with chlorine as a sanitizing agent and the need for a chlorine source. So it's apparently not a "competing alternative sanitizer" as they state but (perhaps) only a complementary one,
   
2. Plus if it's an outdoor pool, you still have to use some cyanuric acid or a pool cover to keep it from "burning off" too fast. So we haven't done away with cyanuric (or a pool cover),
   
3. And folks that keep their pool in-balance never develop algea and so "never" even think about adding the nasty staining metals (aka algecides) they whine about into their pool,
   
4. They do tout this hydrolysis system as neutralizing the bad smelling and eye-burning "combined chlorine" (which this site sometimes misattributes to "high chemical levels"), but folks with light pool loads never have this problem, and folks that do can shock the pool with a dose of chlorine or MPS,
   
5. The system is touted to reduce "excessive chemical damage to equipment and pool surfaces", but correct me if I'm wrong, but this is primarily due to owners not keeping their water balanced (pH, calcium hardness, etc.), and this system doesn't do anything about that.
   

Then there are the questions about how efficiently hydrolysis (splitting water molecules with an electric current) is as a santizer, if it even is an effective complementary sanitizer at all.

Any thoughts?

[chem geek]

Like any system that does its work in the circulation system, such as ozone, UV, or oxygen free radicals, it does not provide any residual sanitizer in the bulk pool water. So it does nothing to prevent pathogens from growing on pool surfaces nor to prevent algae growth there either. This is why they require a residual sanitizer such as chlorine or bromine. This oxygen system is for supplemental oxidation of bather waste and other organics and perhaps for some additional sanitation against pathogens for which chlorine is not very effective such as Cryptosporidium. So this is something quite reasonable for a high bather load pool such as a commercial or public pool since chlorine often has a hard time keeping up with such bather load and Combined Chlorine (CC) is more of an issue. It might also be of some use for even lighter load indoor pools where there is no sunlight (UV) to aid in breakdown of CC.

Your analysis is correct in that a properly managed residential pool has no need for this sort of system. There are tens of thousands of pool owners who maintain their pools using chlorine alone with no need for algaecides, phosphate removers, metal ions, clarifiers, flocculants or weekly shocking. My 16,000 gallon pool (shown here and here) has a mostly opaque electric safety cover so the chlorine usage is fairly low at just under 1 ppm FC per day. The pool is used every day for 1-2 hours and longer on weekends and is kept warm at 88ºF for use as a therapy pool. I add 12.5% chlorinating liquid twice a week plus a small amount of acid every month or two. This costs me $15 per month. I almost always measure <= 0.2 ppm CC. It doesn't get much simpler nor less expensive than that. Also, the local pool store where I get my chlorinating liquid reuses the bottles so it's better than recycling. Read more about how to maintain your pool at the Pool School.

As for the effectiveness of oxygen and hydroxyl free radicals, these are strong oxidizers but there are no current standards measuring how many such free radicals are being produced compared to just creating oxygen (and some chlorine) instead. Technically, when hypochlorous acid breaks down in sunlight, it first forms hydroxyl radicals which is part of the reason that outdoor pools exposed to sunlight seem to handle CC better than indoor pools. Direct UV has some effect as well and the differences in air circulation also play a large role.

[Dark Helmet]

Thanks chem geek. As always I learned a few things from your post.