Waterco Hydroxypure

[Khal_Sagan]

Hi all,

Let me first begin by stating very clearly that I'm a pool designer and builder from Singapore, and that I have no affiliation whatsoever with Waterco or any other pool product company.

TFP has been of immeasurable help in the course of my education, and the Pool School has been vital in allowing me to understand pool chemistry and care methods. I do appreciate greatly the posts by chem geek amongst many others.

This is why I'm writing here today(my first post) - I understand that a recent thread has been closed because of suspicion over the identity of several of the posters. I do not want to step on any toes so do let me know if you have any problems with this post.

I have a client right now who is highly interested in the Hydroxypure system. I am naturally skeptical about non-chlorinated and no-SWG systems, and have often dissuaded my clients against using them. However, I did encounter the Hydroxypure system at Piscine Splash Singapore in 2013 and have been impressed with the product. Consequently I asked for any test reports they might have and they have been sitting in my inbox the past year. I understand there are some doubts regarding the efficacy of peroxide as far as killing bacteria goes. The following is what Waterco replied with last year:

1. Efficacy Sanitizers – this is the standard that the Waterco Brand hydrogen Peroxide was tested to
2. Registered Pool Sanitising Products – The product that Waterco has registered on the list is Sanosil Super (50% concentration)
3. Registered Spa Water Sanitising Products – The product that Waterco has registered on the list is Spa Poppit Spa Conditioner, Clarifier & Bacteriacide(15% concentration)
4. ALS Test Report – independent test report with Hydroxypure system on high load domestic pool 60,000 litres.
5. Plate Testing Guide used as part of the ALS testing procedure.

My question is if the addition of Sanosil Super and Spa Poppit does make any difference, and if it does, would any of you feel it's a sufficiently safe product to install in a residential pool?

Again, I appreciate any insight you guys might have.

Robin

 

[chem geek]

Hydrogen peroxide certainly makes a difference. The issue isn't whether it disinfects at all or oxidizes at all, but whether it does so quickly enough to a large range of pathogens in order to meet the criteria as a swimming pool disinfectant. I posted links in this post that showed that hydrogen peroxide even with silver ions killed some pathogens way too slowly to be considered a swimming pool disinfectant. As for swimming pools, this paper indicates that silver ions combined with hydrogen peroxide in the Nanosil product at 20 mg/L (ppm) prevented uncontrolled bacterial growth but killed Staphylococcus aureus slowly requiring 20,000 ppm for 30 minutes (a bacterial species chlorine kills in seconds). Also, this link shows hydrogen peroxide to be ineffective against bacteria at swimming pool concentrations. In fact, it showed log reductions lower than 0.301 (a 50% kill rate) in 30 minutes against Pseudomonas aeruginosa (0.16-log reduction) and Escherichia coli (0.13-log reduction) and just 0.33-log reduction after 30 minutes for Staphylococcus aureus and just 0.41-log reduction for Legionella pneumophila. This isn't even enough to prevent uncontrolled bacterial growth under ideal conditions for such growth. However, something smells fishy about this study because they found no improvements when using silver ions in the water. Other studies have shown silver ions to have at least a slow kill against fecal bacteria. This paper in Figure 2(a) shows 1.5 hours for a 3-log reduction of Staphylococcus aureus with silver ion at 0.05 ppm (50 ppb) while Figure 2(b) shows around 20 minutes for a 3-log reduction of Escherichia coli at 0.05 ppm (50 ppb). The Borgmann-Strahsen study used 23.6 ppb silver so perhaps this difference is a minimal inhibitory concentration effect (23.6 ppb vs. 50 ppb for silver).

It is not approved by Health Canada nor by the EPA in the U.S. nor by the DIN 19643 standard used by some countries in Europe, but it is approved on its own only for spas by Australia (there is one product approved for pools Poppit Sanosil Pool & Spa Sanitiser that also has silver ions, but the label requires it to be used in combination with Polyhexamethylene Biguanidehydochloride while Poppit Sanitiser which is hydrogen peroxide alone says "The level required for spas is lOOppm of hydrogen peroxide (see chart) and for swimming pools is lOOppm" and cannot go below 40 ppm, according to label instructions. There is no product listed under APVMA called "Sanosil Super" -- search PUBCRIS yourself and see what you can find, so perhaps that name is covered under the Poppit Sanitiser registration. There are a bunch of hydrogen peroxide registrations, but only three where two are for use in spas ("POOL SANITISER" is the category for disinfectants able to be used in pools and spas, two of which I mentioned already with their limitations -- SPA FRESH SPA SANITISER, CONDITIONER, CLARIFIER & BACTERIACIDE appears to be for spas only).

For the EPA, one of four approved disinfectant chemical systems is Baquacil/biguanide/PHMB and it uses hydrogen peroxide as an oxidizer, but the disinfection is from the biguanide. Hydrogen peroxide alone is apparently not able to pass the stringent laboratory efficacy portion of the test that requires 6-log kill of some fecal bacteria in 30 seconds -- basically what 0.4 ppm FC of chlorine is able to do (with no CYA).

If you have more details on the presumably laboratory testing "efficacy sanitizers" tests, then that could be helpful. And you might question the company against the PUBCRIS database and be very, very specific with them. I suspect that "Sanosil Super" is using the registration for "Poppit Sanitiser".

As for whether this is good enough for a residential pool where the risks of person-to-person transmission of disease are lower, that's a personal question and generally residential pools and spas are not regulated with regard to what chemicals you put in -- regulations are generally for commercial/public pools/spas and for labels/claims on pesticide products. We generally recommend sticking with chlorine that has been proven to be a very effective disinfectant and whose active chlorine level can be set readily to prevent algae growth. We have no experience with how well hydrogen peroxide alone controls algae growth.

 

[Khal_Sagan]

Hi Chemgeek,

Thanks again for your very comprehensive response. I have since cautioned my client against using this system and will be steering clear of it for now. In the meantime, I shall write Waterco and ask for the information that you mentioned. Hopefully, I'll get some clarity and will return with my findings.

Robin