Excess Chlorine Loss (Ozonator?)

[Trailanimal]

So, was a bit perplexed recently with an increase in FAC loss. Without soaking, I'm losing 4ppm every 24hrs, which seems excessive. It was about 2ppm a few weeks back. I then realized I increased my filter time from 1hr every 12 hours to 2hrs every 12 hours. I then checked FAC before/after each filter cycle for 2-days and wouldn't you know, in all 4 cases the FAC was 2ppm lower. The ozonator only runs during filter cycles.

My water Chemistry is at TFP recommendations...TA=50, pH=7.6, CC <0.5ppm, CYA ~30ppm, etc. I try to keep baseline Chlorine around 3-4ppm. 4hrs of filter cycle is well within normal limits, though I didn't have any issues before increasing from 2hrs. 2hrs just seemed a bit low from what I was reading. Any reason to be concerned with adding an extra 2ppm FAC to daily maintenance? Bathing load only adds 0.5-1ppm per person per 30-45min soak. Last CYA test was about 4-5wks ago as well.

 

[ajw22]

Ozone Systems - Further Reading

www.troublefreepool.com

 

[phonedave]

So, was a bit perplexed recently with an increase in FAC loss. Without soaking, I'm losing 4ppm every 24hrs, which seems excessive. It was about 2ppm a few weeks back. I then realized I increased my filter time from 1hr every 12 hours to 2hrs every 12 hours. I then checked FAC before/after each filter cycle for 2-days and wouldn't you know, in all 4 cases the FAC was 2ppm lower. The ozonator only runs during filter cycles.

My water Chemistry is at TFP recommendations...TA=50, pH=7.6, CC <0.5ppm, CYA ~30ppm, etc. I try to keep baseline Chlorine around 3-4ppm. 4hrs of filter cycle is well within normal limits, though I didn't have any issues before increasing from 2hrs. 2hrs just seemed a bit low from what I was reading. Any reason to be concerned with adding an extra 2ppm FAC to daily maintenance? Bathing load only adds 0.5-1ppm per person per 30-45min soak. Last CYA test was about 4-5wks ago as well.

To answer your question. No, there is no reason to be concerned with adding an extra 2ppm as part of your daily maintenance. In fact you can go up to SLAM levels just fine.

My hot tub, with ozone, consumes 2 ppm of FC daily until it gets to around 3 ppm, then it seems to slow down.

I know there are people here who are going to be reaching for the AED when I say this, but I don't test and dose my hot tub on a daily basis. I go a day or two between. Sometimes I know nobody is going to be using it for the next two days, so I run the FC up higher and let it sit. Other times I do things differently. The thing is, my hot tub is CLEAN. It gets purged every time I change the water and it gets AquaClarity weekly. I also keep on top of the non-daily maintenance (cleaning filters, wiping down the shell, etc). The upshot is, with the cover on, there is not much in there to deplete the FC except for the ozone, and there is not much of anything in there that can grow. If I have not added chlorine for a day or two before I want to use it, I test for CC's. If nothing is there, then I add bleach and get in the tub.

Part of it may also be that that only people that really use the hot tub are my wife and myself. We had dedicated hot tub swimsuits, we don't get hair product or other stuff in the tub, we don't use the tub as a bath, etc..

 

[Dave95602]

We have a two year old Optima, and just last week decided to unplug the ozone generator. I am balancing chems most days, and often adding 3-4 oz of 10% chlorine, even on days when the spa was not being used. I was considering switching to a salt system, but decided to try running without the ozone first. It's still early, but so far it looks like I'll be adding about half as much daily chlorine.

 

[phonedave]

We have a two year old Optima, and just last week decided to unplug the ozone generator. I am balancing chems most days, and often adding 3-4 oz of 10% chlorine, even on days when the spa was not being used. I was considering switching to a salt system, but decided to try running without the ozone first. It's still early, but so far it looks like I'll be adding about half as much daily chlorine.

In my mind ozone is a zero sum situation.

If your ozone works really well, and does a great job reducing pathogens, then it is also going to be doing a great job of reducing your FC

If on the other hand you ozone is not doing much to kill pathogens, the it is likely not doing much to drive down your FC either.

 

[Dave95602]

Agreed. Ozone is probably providing some benefit, but it is difficult to quantify. All I know is ozone alone does not keep my tub safe/clean, as can be seen when I occasionally fail to keep proper Cl levels. I'd rather rely on Cl, which I can measure/control. And I'd rather have the Cl last longer, particularly when I get busy or distracted and neglect our tub.

 

[RDspaguy]

Agreed. Ozone is probably providing some benefit, but it is difficult to quantify. All I know is ozone alone does not keep my tub safe/clean, as can be seen when I occasionally fail to keep proper Cl levels. I'd rather rely on Cl, which I can measure/control. And I'd rather have the Cl last longer, particularly when I get busy or distracted and neglect our tub.

Ozone is an oxidizer, so a shock. It depletes chloramines must faster than fc. Eliminate it and you'll have to shock manually to reduce cc, resulting in excessive and even temporarily unuseable fc levels or requiring non-chlorine shock. Just like a pool with heavy bather load.
I won't go on another rant about the benefits of ozone, my views can be easily found here, but if conserving chlorine is your only concern then I'd say the ozone is doing a great job. Not sure you'll save much $, but your experiment might illustrate the value of ozone to you.

 

[Dave95602]

...but your experiment might illustrate the value of ozone to you.

I hate to say you told me so, but... I'm leaning towards reconnecting the ozone generator.

With the kids home for the holidays, the tub has been getting more use and while clear, it has that certain odor I associate with chloramine buildup.

Thanks for letting me know about ozone and chloramines, I had no idea.

 

[RDspaguy]

Thanks for letting me know about ozone and chloramines, I had no idea.

Then my time here has not been wasted.