Does ozone really deplete FC? I'm getting conflicting advice...

[davesurfer]

I have an ozonater in a tub that was purchased back in '94. The nipple broke off of it and so I put a new one on. I've had a few people tell me just to unhook it from the power supply and seal the air intake. So I've done that. Now I don't see any little bubbles coming up from the bottom like there used to be.

I look at sites like this Swimming Pool Equipment: Ozone Generators where ozone is said to be natural and a safe way to sanitize...other people say it uses up all the FC. I don't even know if it's working and to test it is cheaper than just replacing it with another ozonater so...

Opinions?

 

[JVTrain]

Ozone can be a helpful secondary sanitizer when used in spas that are employing bromine and are used frequently. Notice I said: secondary sanitizer, with bromine and frequently used.

1- Ozone alone does not have fast enough kill times or whole spa presence like chlorine or bromine. It's only helpful in helping your primary sanitizer do its job.
2- Ozone can oxidize residual bromide in the tub back to active bromine, helping recharge your bromine levels. Not a huge amount but enough to make some difference. It does not have a similar mechanism when chlorine is used.
3- Ozone works well when spas are used frequently because the ozone is oxidizing organics. In an unused spa, ozone can actually slowly oxidize some of your free chlorine or bromine, increasing your daily FC consumption. Ideally, the ozonator is only running during soaks and for a time after soaks, but most spas are not set up to run ozonators this way. They simply run whenever the pumps are running.

 

[Donldson]

JV touched everything really to be said, I just want to point out that the phrase "Safe and Natural" is nothing but marketing speak. Ozone is as natural as any other chemical you add to your spa. It can also be just as safe or unsafe as any other chemical, depending on the concentration. The link you posted is to a company that happens to sell ozone systems. As such any claims are designed to sell their product and should be taken as such unless verified by unaffiliated sources.

Just keep that in mind, you will find a lot of different claims by pool and spa companies trying to sell you their product or system. Some stick to the facts, most will stretch those facts a bit to help boost their image, and some will straight up use fear tactics and/or lie.

 

[davesurfer]

So really I should just hook it back up then. It seems to run all the time though, because I see a trail of tiny bubble always coming up when it's hooked up. Unless it just puts in air all the time and then activates the ozonator when the pump is on.

 

[BuckeyeChris]

does it have a power light on the unit, that would indicate if it's powered and functioning all the time, or just when the pump runs?

 

[Brian VT]

If the ozonator is from '94 then it's not adding ozone to your water. They usually only last 2-3 years.
Those that don't feel that they're worth replacing block off the intake and forget about it.

 

[Isaac-1]

Just to back up and expand on what Brian VT said, older ozonators would tend to stop producing Ozone after 2-3 years even if the power light was lit, to determine function on marginal units, there are single use tests that involve drawing the ozone through a glass tube and watching for color changes. Personally I don't think older units are worth testing since the test costs about $15 and replacement units sell for a bit over $100 online. There are some newer units that have actual built in indicators for ozone production not just power lights, some also have replaceable modules for when they stop producing ozone. Also some of the newer models have a 5-7 year life so they are not only cheaper, but last longer than old units.

 

[JoyfulNoise]

In case anyone is interested in the detailed chemistry, it has been worked out previously HERE.

 

[JamesW]

https://www.absoluteozone.com/assets/ozone_for_municipal_spa_and_pool_treatment.pdf
See this reference that shows that the reaction of ozone with chlorine.
Chemistries of Ozone for Municipal Pool and Spa Water Treatment Facts and Fallacies
Rip G. Rice, Ph.D.

The net result is 77 % chloride and 23 % chlorate.