Ozone and chlorine

[KB1984]

Hey,
I've had our hot tub since November and have a pretty good handle on things but just added an ozonator. I understand chlorine can now be 0.5 ppm but how do I actually know if my ozonator is actually doing anything? I installed it and do know it powers on, is plumbed in correctly, flows when the jets are on and adds ozone right before entering the tub via a jet. It only runs during filter mode and that jet is on that pump as well. I'm familiar with ozone smell from other air purifiers but I don't smell any of that. I've had it installed for a week or so. Sure, I can check my chlorine and make sure it's lower now but if the ozonator isn't working or working well then I just get unsafe water without knowing. Someone said you know because small air bubbles come out of the jet. Well, the ozone only runs when the jet is on so that's going to happen to some extent regardless.

Do I not smell ozone because I didn't change the water because it's currently -30 outside... Since the water is a couple months old I can see needing time to catch up, or should I notice something by now? There is a small change in smell but I wouldn't say ozone like our air ones are. Before plumbing in I did turn it on and did smell some ozone so should be working.

I should add that I currently have the filters/ozone running from midnight for 5 hours. Then noon for 3 hours. Maybe someone has suggestions on that or if that amount of time is ok.
Thanks for the help!

Kevin

 

[ajw22]

Welcome to TFP.

What model hot tub do you have?

What ozonator did you install?

Read what @RDspaguy says about ozone in a spa at these links and maybe he will elaborate when he wanders by…

Search results for query: Ozone

www.troublefreepool.com

 

[KB1984]

I don't remember the model of the tub. Be well 5 person I believe, about 450 gallons with a gecko controller.

The ozonator is a Clarathon HCD-55 Hi-Output Spa Ozonator Kit

 

[ajw22]

It is difficult giving advice on your hot tub operation with ozone without knowing the model and what controls it has.

 

[KB1984]

It is difficult giving advice on your hot tub operation with ozone without knowing the model and what controls it has.

Understandable. I guess I was just thinking I know the ozonator is receiving power at the correct times. The venturi injector is flowing and creating vacuum as expected. The machine itself if making an ozone smell just not obvious in the tub yet. So I know it's all working in theory. But does it take time since the water is a couple months old? Do I need more circulation time? And when the ozonator does die, how do you know other than green water?

Be well spas O665
Gecko IN.YE-5-H4.0

 

[ajw22]

I should add that I currently have the filters/ozone running from midnight for 5 hours. Then noon for 3 hours. Maybe someone has suggestions on that or if that amount of time is ok.

For ozone in a spa to be effective it needs to run 24/7 so that you have around 5 turnover of water per day. Ozone is an oxidizer and only affects water it comes in contact with through the cell. You need about 5 turnovers to get 99% coverage of the water through the ozonator.

Turnover of Pool Water - Further Reading

www.troublefreepool.com

8 hours per day does not affect your water enough that you can reduce your chlorine level.

Maintain your chlorine to have a safe sanitary pool.

For more read what @RDspaguy said here…

Installing an EOS ozone generator in a Bullfrog R7 hot tub

We got our Bullfrog R7L in late September of this year, my first hot tub. We love the tub. The jets, the quiet circulating pump, the simple controls, it all worked great. I did start having problems with the Frog@ease water care system when the water got cloudy. I dumped the water and decided to...

www.troublefreepool.com

 

[RDspaguy]

and adds ozone right before entering the tub via a jet.

If the hose from the ozonator goes to a jet air intake you will destroy your spa cover, pillows, and everything else under the cover and above the water line.

I understand chlorine can now be 0.5 ppm

Not really. The ozone, if doing it's job, will reduce the chlorine to 0.5ppm overnight. While clean and sanitary, this provides no protection from bather-to-bather contamination, it is like a fresh fill. This is only if you add enough chlorine after use to sanitize the spa.
If plumbed as discussed above, the ozone will not have a noticeable effect on the water.

only runs during filter mode

You will see no effect unless you run excessively long filter cycles. The ozone systems that made ozone popular were 24/7 systems.

Someone said you know because small air bubbles come out of the jet.

The ozonator does not pump anything, it needs a suction (vacuum) line from another source, usually a mazzie (venturi) inline on a circulation pump return, but every jet has a venturi built in and can be used to put ozone in the tub. Again, under those circumstances it bubbles to the surface and collects under the cover, doing next to nothing for your water.

The machine itself if making an ozone smell just not obvious in the tub yet.

You should not smell ozone, just fresh water with no chemical odor.

But does it take time since the water is a couple months old? Do I need more circulation time?

The water gets sanitized by chlorine. This produces combined chlorine (cc) which is what you smell when you smell "chlorine". Oxidation (aka "shocking") burns off cc. Ozone is a powerful oxidizer, so powerful that it burns off excess chlorine (free chlorine, fc) after it finishes off the cc. But it takes exposure, which takes circulation and contact.
Again, worse than useless if plumbed directly to a jet.

For ozone in a spa to be effective it needs to run 24/7 so that you have around 5 turnover of water per day.

On a 24/7 circulation system with a known approximate flow rate (about 10gpm with a laing pump) you will turnover the average (350 gallon) spa every 35 minutes. 5 turnovers (they say) will get 99% exposure, so every 3 hours or so. Bigger spas take a little longer.
On a secondary jet line from the main pump, flow rate, and therefore turnover, is impossible to know without installing a flow meter, but will be significantly less even if run 24/7.
The cost and wear of running the main pump enough to benefit from ozone is also a consideration. I do not recommend ozone for these systems.

when the ozonator does die, how do you know other than green water?

Chlorine smell. This is assuming it was doing any good to begin with. Green water means not enough chlorine to sanitize. Because it does not establish a residual (build up) in the water, ozone only effects the water it contacts, which it returns to a contaminated tub. If there are contaminants in the tub that are multiplying (such as green algae) the ozone will not keep up with it.
Bear in mind, it says to keep a minimum of 0.5ppm fc AT ALL TIMES, and 0.5ppm fc wil be used up by you dipping your feet in the spa. To keep a minimum 0.5ppm, you must start with enough to handle the (unknown) contaminant load you introduce plus 0.5ppm. If you can figure out a way to calculate that let me know.
If cross-contamination in your private spa is not a concern to you, then you can enjoy a "low chlorine" soak with little risk, but you still have to sanitize the water after use.

8 hours per day does not affect your water enough that you can reduce your chlorine level.

Again, it is the ozone itself that causes the reduction in fc. This does not mean you will use less chlorine. You still need to add enough to kill the organic contaminants you introduced by using the spa. What you don't have to do is shock, or deal with high chlorine levels from shocking or too much chlorine, or worry about using too much so you don't use enough, or panic because you forgot to add chlorine for a few days of non-use, or smell chemicals or musty odors in your spa and on your skin.
Of course, you gain none of these benefits without adequate exposure, which is difficult and expensive to get on the main pump, and impossible to get if plumbed to a jet.

The ozonator is a Clarathon HCD-55 Hi-Output Spa Ozonator Kit

Ozone output is one variable in the equation, but it should be matched to the flow rate of the injector. A high output ozonator on a low flow injector (venturi) will destroy itself and possibly other equipment under the spa and clog the venturi with nitric acid goo.

 

[KB1984]

Thanks for the info. You mentioned things like with this setup etc... But didn't offer a solution. I am realizing the ozonator instructions were horrible and don't really explain anything. I do not see anything in my spa to indicate it's ozonator ready even though it's new. So I had to add it all without any clear direction. All it shows is the ozone line into an Venturi and then into the tub which appears to be through a water jet, so that's what I did. But didn't have enough suction to add ozone into the water.

You said it's basically pointless if though a jet. So then how do you add the ozone into the water if not via a venturi right before a jet? Are you saying it needs its own wall inlet (wrong word probably) into the tub? I did order one, basically a 3/4" barb that doesn't have much reduction, in other words just flows into the tub with nothing narrowing it or spinning, etc. My plan was to tee off of the 3/4 line that only feeds one jet which is used at the bottom for circulation. The downside and part I was trying to avoid is cutting a hole into the tub to install its own inlet.

 

[5tan]

8 hours per day does not affect your water enough that you can reduce your chlorine level.

You haven't seen a Bullfrog EOS3 ozonator work then. Each hour with this EOS3 on will drastically drop FC, this thing is powerful. 8 hours will drop 10ppm FC to the 0-2 range. I have custom ozone runtimes based on bather load / lack of any bathers.

I understand chlorine can now be 0.5 ppm

This is not correct. Regardless of the presence of an ozonator, regardless of presence of enzymes, copper/silver/other minerals/etc, regardless of anything else, you always need at least 3ppm FC to minimize transmission of infectious pathogens. The ozonator's job is performed AFTER making people soup. In simplified terms, the purpose of using ozone is to break up difficult-to-break compounds formed AFTER people soup and free chlorine mix together. Pretty much all brands/models of spa controller packs specifically disable ozone whenever the spa is in use and for 20 minutes after the last button was touched. Therefore, it's clear to see that the ozonator's job takes place only after you get out of the water.

You said it's basically pointless if though a jet. So then how do you add the ozone into the water if not via a venturi right before a jet?

Passing ozone through a jet and just blowing ozone gas into the water without thorough mixing will have near zero effectiveness, just a waste of electricity to run the ozonator at that point, and causing harm to whatever the gas touches after it offgasses (hot tub covers, overhanging vegetation, lungs of nearby living things, etc). An effective way to ozonate water is to utilize a separate mixing chamber and where the gas is filtered/exhausted safely. You should look up ozone mixing chamber designs (e.g. Bullfrog EOS3 will give you an idea of how to do it on a small scale).

 

[RDspaguy]

There is no problem with using an existing jet water line, the issue is exposure time.
The best explanation I have heard for ozone (and I have no idea if this is true, I couldn't even tell you where I heard it) is that it is not the ozone that does anything, it is the ozone breaking down that oxidizes. Ozone (O3) is created by passing oxygen (O2) through UV radiation causing a molecular bond that becomes unstable once outside of this uv. As the O3 breaks down into 02 it releases "O1" (if you will), which is the oxidizer (free radical). This takes time (about 30 seconds, give or take), and the ozone must be in contact with the water and as diffuse (tiny bubbles) as possible.
Effective ozone systems inject into a water line on an independent pump via mazzie, then that water line runs for some distance and passes through one or more diffusion chambers (ozone mixing fitting) and enough pipe to ensure that the ozone has all broken down to oxygen before entering the tub.
Many other tubs, wanting to jump on the ozone bandwagon started by D1, Sundance, and Hot Springs, would install an ozone generator, but run the hose to the air intake on the jet itself, injecting directly into the tub. The ozone then rises to the surface as ozone, where it breaks down under the cover oxidizing the water surface, cover, pillows, etc.
To make your aftermarket install work you will have to add some 20ft (depending on flow rate) of 3/4" hose between the mazzie and jet, and put a diffuser or 2 along the way. Even then, running off the main pump, your ozone water line is getting an unknown flow rate, but it will be less than the other jet lines due to mazzei valve, diffusers, and extra hose. Ideally, you would want a circulation pump plumbed in specifically for the ozone.

 

[KB1984]

There is no problem with using an existing jet water line, the issue is exposure time.
The best explanation I have heard for ozone (and I have no idea if this is true, I couldn't even tell you where I heard it) is that it is not the ozone that does anything, it is the ozone breaking down that oxidizes. Ozone (O3) is created by passing oxygen (O2) through UV radiation causing a molecular bond that becomes unstable once outside of this uv. As the O3 breaks down into 02 it releases "O1" (if you will), which is the oxidizer (free radical). This takes time (about 30 seconds, give or take), and the ozone must be in contact with the water and as diffuse (tiny bubbles) as possible.
Effective ozone systems inject into a water line on an independent pump via mazzie, then that water line runs for some distance and passes through one or more diffusion chambers (ozone mixing fitting) and enough pipe to ensure that the ozone has all broken down to oxygen before entering the tub.
Many other tubs, wanting to jump on the ozone bandwagon started by D1, Sundance, and Hot Springs, would install an ozone generator, but run the hose to the air intake on the jet itself, injecting directly into the tub. The ozone then rises to the surface as ozone, where it breaks down under the cover oxidizing the water surface, cover, pillows, etc.
To make your aftermarket install work you will have to add some 20ft (depending on flow rate) of 3/4" hose between the mazzie and jet, and put a diffuser or 2 along the way. Even then, running off the main pump, your ozone water line is getting an unknown flow rate, but it will be less than the other jet lines due to mazzei valve, diffusers, and extra hose. Ideally, you would want a circulation pump plumbed in specifically for the ozone.

Thanks for the info, that helps and does make sense! I plan to redo what I did when its a bit warmer. That totally makes sense and may have made the exact same error again. I ordered in a 4 foot chunk of hose so id have extra haha, so I guess I need to go buy some more. I was actually thinking that, wondering if I should be injecting to O3 closer to the pump to give more hose with O3 or right outside the wall inlet. Now i know better!