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Question:

I am looking for the least toxic, healthiest way to maintain a hot tub without chemical shock. I an using a copper/silver sanitation system, but am still told I need an "oxidizer" to burn off organics when I exit the spa (bromine, chlorine, potassium monopersulphate). I wanted to test the level of ozone in our water to see if the unit is putting out enough. Do you have test strips that I can use in my spa? I am told that ozone is a great oxidizer (my unit came with an ozone generator) but it isn't doing the trick. My question is could the ozone be at too low a level (i.e. an inferior generator) or would I be able to use hydrogen peroxide as a shock (and would that be compatible with the copper/silver system? What would you recommend if I wanted to boost the levels of ozone with one of your machines? (which model would you recommend?)


=== Hello

=== You have number of very good questions....so, I will try my best to deal with them one by one:

 

I am looking for the least toxic, healthiest way to maintain a hot tub without chemical shock.

=== That will be in my opinion ozone or hydrogen peroxide.

 

I an using a copper/silver sanitation system, but am still told I need an "oxidizer" to burn off organics when I exit the spa (bromine, chlorine, potassium monopersulphate).

=== That is correct.

 

I wanted to test the level of ozone in our water to see if the unit is putting out enough. Do you have test strips that I can use in my spa?

=== Ozone in water is relatively difficult to test because of the presence of copper/silver ions and chlorine in water will effect ozone readings. However, there are chemical tests for ozone produced by LaMotte Co. and there are also electronic tests called ORP (Oxygen Reduction Potential). To my knowledge, there are no simple "test strips" for ozone levels in water (similar to pH test strips).

=== By the way - the copper/silver sanitation is based on toxicity of these two metals to microorganisms....consequently, I would be inclined to believe copper/silver sanitation systems as toxic to humans as well.

 

I am told that ozone is a great oxidizer (my unit came with an ozone generator) but it isn't doing the trick.

=== To my knowledge ozone is very powerful oxidation agent, however there are number of aspects to consider when dealing with ozonation:

  1. concentration of ozone gas
  2. total impurity load
  3. efficiency of mixing process (ozone & water)
  4. exposure time (ozone & water)

=== I am not surprised at all to read that ozone generator which was an integral part of your spa, does not do the job....this is because of following reasons:

  1. ozone concentrations produced by ozone generators usually used for spa is simply too low - spa producers and dealers prefer to use UV ozone generators because they are dirt cheap....
    1. adding UV generator to spa package "free of charge" is actually very nice looking marketing trick....
    2. you will still need chemicals - guaranteed sales for spa retailers
    3. you will need replacement UV bulbs - even more sales for retailers
  2. Total impurity load can be very high due to relatively small volume of water for relatively large number of people bathing in water. Plus - high water temperature has very negative effect at efficiency of ozone.
  3. recirculation in standard spas is usually not sufficient for ozonation (too slow). To make whole situation even worse, spa producers usually use low cost/low efficiency injectors (ventury) to mix ozone to water.
  4. exposure time between ozone and water is also limited by fast decomposition of ozone in warm water.

 

My question is could the ozone be at too low a level (i.e. an inferior generator) or would I be able to use hydrogen peroxide as a shock (and would that be compatible with the copper/silver system?

=== There is no doubt in my mind that an ozone generator supplied with your spa is UV based unit - which simply is not powerful enough to deliver any better results than you already observed even if you will improve mixing and circulation (costly).

=== I would prefer not to use copper/silver sanitation....

=== ....and I would focus my attention to a combination of your existing ozone generator with H2O2.....

I personally used to be involved in installations of small corona discharge ozone generators (200mg/hr with 2LPM flow) for spas, however we do not use "ozone alone" any longer. There are high risks involved when dealing with ozone only......bacteria will start to multiply in warm water really fast as soon as ozonation will be disrupted. That can be result of:

  1. failure of the pump
  2. failure of the ozone generator
  3. power outage
  4. any possible problem with ozone tubing & connections
  5. etc....

....and these are just a few examples.

=== When H2O2 is used as a primarily sanitation agent all problems associated with vulnerability of ozone systems are eliminated. When regular H2O2 dose is delivered to water, then we know that H2O2 is there....and ozonation can be used as a support treatment to lower the expenses for H2O2.

 

What would you recommend if I wanted to boost the levels of ozone with one of your machines? (which model would you recommend?)

=== The boost of ozone levels by adding an other ozone unit (or replacing existing ozone generator) may improve significantly the quality of water in your spa, however this solution is not going to give you any protection against the problems with ozonation of spa I outlined earlier.

In any case, I would like to encourage you to consider H2O2 as a primarily sanitation agent.

You may wish to check out our infomration about H2O2 test strips.

We also have an article in our Articles Area specifically on H2O2 which you may find useful...

=== Take Care

=== Den Rasplicka - Ozone Services


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