The Truth About Ozonators in Spas

[Chas]

Some tub makers use a simple length of 'spa flex' tubing, which has a gentle spiral built in. The HS and TR tubs have somewhere around 12 - 14 feet of the stuff, and it's installed on all the tubs, even though the TR tubs do not come standard with ozone. They are 'ozone ready.'

Some companies use a large 'off-gas vessel,' which is some sort of larger-diameter pipe, maybe 10 or 12 inch diameter, with the ozone being introduced at the bottom, and the water flowing in the opposite direction. Then they capture the off gas at the top of the vessel and re-inject it somewhere in the system. Here is Del's MDV:


Other folks have other ideas. I think they all do about the same thing, and I like the simplicity of the HS system. I have retrofit ozone to HS tubs without the contact chamber, and it began to burn the cover, especially right above the return fitting. Also there was a heavy ozone odor when you first opened the cover - unless it happened to be breezy at the moment...

I went back and added a coiled up piece of spa flex - gently looped around the motor compartment a couple of times, and the burning and smell both stopped.

[In Canada eh]

Chas,

Still working things out about UV but I saw that off-gassing vessel(bubble trap) on the web sight you posted.  It looks like a get idea, wouldn't it save you alot of space on retro fits.  We use bubble traps on all kinds of instrumentation and they work great

[Chas]

I don't do many retrofits, since HS has made 'ozone ready' tubs for many years now.

If I do retrofit, I just put in a loop of Spa flex - lay it in the motor compartment when I can - and it works great.

[Vinny]

The funny thing about the Del's (and maybe others) is their secret weapon is activated carbon. BUT once it's about a year old or gets wet it stops working.

I think the long tubing is probably the best idea. Back in 2004 when I looked at D1 they ran the tubing up and down the parimeter of the tub ... but the used a UV ozonator ... as the dealer told me "those CD units aren't as good as the UV units" ... hmmmmm.

That's why it's important ladies and gentalment to find a good dealer ...

If I decide to keep ozone in the tub I was planning on buying a CD unit and 20' of tubing. Somehow I figured I could get some type of connector to attach the tubing together with what's there ... I'm so confused!!

[In Canada eh]

Vinny

Chas posted some great websites on your experiment topic showing various installation ideas.  You could look at the by-pass style or the off gas vessel, both would be easy and look like they would work well

[Vinny]

I actually looked at the Del vessel and found a couple of things that "wouldn't work". First, is what I mentioned - I can't see how any water won't get the activated carbon filter wet. The second is the flow rate at which the vessel can take the circ pump. My pump is advertised at 11 GPM and I think the Del can only go to 8 without some additional plumbing.

I will look at the other websites to see exactly what available. I won't be doing anything to the plumbing until after the warranty, I have 2 more years.

[HotTubMan]

I had an interesting conversation in my store a few weeks ago. The gentleman I spoke with claims to be working with a former NASA scientist on a O1  system to purify water. He claimed it would sanitize sewage (which would leave sediment at the bottom that would require filtration. He claimed the water skimmed off the top met or exceeded all standard of water purification.

This system has a generator that creates a single oxygen molocule that according to hit is a much more powerful oxidizer than O3.

He claimed his brothers hot tub has been used as a prototype and uses absolutely no other sanitizer.

I was intrigued, but sceptical.

If I hear more I wil share.

[Gomboman]

This is a very interesting thread. Chas, are you saying that my contact chamber for my spa (HS Envoy) is a 14' piece of tubing that is wound up in my footwell area? The only reason for this is to prevent off gassing? Does the tubing ever get damaged from the ozone? I bet it would be difficult to remove or replace the tubing.

There still seems to be some controversy whether or not ozone is actually effective? Are there any independent experiments conducted in the spa industry on the effectiveness of ozone? If so, I would like to read the report.

[HotTubMan]

Gombo, I dont have any clinical evidence to present.

What I have been taught is that O3 has a very short half life in water. Somewhere around 30 seconds.

Airborne ozone could last 30 minutes.

As far damage to the pipe, that is a good question.

The goal of that 14' foot pipe or any intelligent ozone system would be to trap the ozone in the water for 30 seconds. Otherwise it becomes airborne between your water and cover and WILL damage the cover and pillows etc.

If the ozone is trapped long enough, the bubbles floating to the surfac e are simply oxygen.

[Gomboman]

OK, so the goal is to trap the ozone for 30 seconds and then release it into the spa? I'm assuming if you trap it too long the ozone will be depleted and offer no benefit?

[DPS]

The "life" of ozone in 100 degree water is 22 seconds.  After that it isn't helping or hurting anything.  If the ozone only stays in the water for 10 seconds or so, half of it is wasted.  This wasted ozone can have a harmful effect - causing damage to covers, headrests, lungs, etc.

[HotTubMan]

OK, so the goal is to trap the ozone for 30 seconds and then release it into the spa? I'm assuming if you trap it too long the ozone will be depleted and offer no benefit?

The work is done in the contact chamber, not in the body of water that you bath in. It is virtually impossible for the ozone to have an effect if injected directly into the spa as it is lighter than the water and would float to the surface and then be trapped by the cover.