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Ozonator and Oxidation?


mscdman

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Still trying to get this water chemistry right and finding my bromine levels are way too high (11ppm).   I have an ozonator.   I seeded the tub with 30ppm bromide salts.  
 

if this ozonator is running isn’t it always oxidizing the bromide thus without any manual shocking after use  - won’t the bromine always be high (too high in this case?)?

trying to figure out why my bromine is so high. No floater being used.  Only the initial seed and ozonator plus occasional manual shock.   

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Stop the manual shock and see.

I don't use bromine, so am not sure how it reacts with ozone in a practical sense. In theory, ozone is an oxidizer and will create bromine from bromide. I have read in the course of researching it that it will also oxidize the bromine, but at a much slower rate than it does chlorine. But that is just a vague statement in a few scientific studies I have come across. 

Also, since some ozonators produce more ozone than others, and different injectors feed it in at different rates, and different systems run the ozonator for different periods of time, and different spas have different volumes, it is nearly impossible to pin down a "normal". 

We would be very interested in hearing the results of your experimentation.

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Update:   Stopped the manual shock and used the tub and the bromine levels are indeed dropping even with the ozone running (note I don’t use a floater w tabs - only initial bromide reserve seed).   In theory if the ozone was constantly oxidizing the bromine at a HIGH  level, the bromine level would be creeping UP not DOWN as I am seeing.    So, still testing for a few more days but indications are that if the ozonator was oxidizing the bromide at a HIGH level you’d see increasing levels of bromine without shock being needed.   And that doesn’t seem to be the case so far to any noticeable degree.  
 

Therefore, I’m theorizing that the ozonator does help with oxidation bromide but not near the level that is needed alone without manual usage shock or a floater.  the next step for me is to continue this test and to see if I can manually maintain the bromine level with manual usage (per usage) of bleach - reactivating the bromide reserve without spiking it too high and having to wait to use the tub
 

 

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Now I have another question though.   Does Bromine naturally lessen/go away in the tub (well it’s rhetorical because it is) when not in use?  Put another way, if you have say 10ppm bromine in the tub one day, what makes it drop from that level assuming no use, no open, no floater etc?  

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4 hours ago, mscdman said:

In theory if the ozone was constantly oxidizing the bromine at a HIGH  level, the bromine level would be creeping UP not DOWN as I am seeing

In theory but not in actual practice. Most ozone generators in tubs are UV and not corona discharge and don't really produce enough to be your primary oxidizer. Also 2 step bromine will keep usually show a drop in bromine over time until you oxidize again.

 

4 minutes ago, mscdman said:

  Does Bromine naturally lessen/go away in the tub (well it’s rhetorical because it is) when not in use?  Put another way, if you have say 10ppm bromine in the tub one day, what makes it drop from that level assuming no use, no open, no floater etc?

In a one step or 2 step system, yes. In a correctly set up 3 step system with a good floater such as the Pentair the bromine levels will stay fairly constant. It can take a lot of trial and error to get the floater adjustment right. When I had a bromine stand along spa many moons ago it took me about 2 months to get the floater adjusted so my bromine levels were constant.

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7 minutes ago, waterbear said:

In theory but not in actual practice. Most ozone generators in tubs are UV and not corona discharge and don't really produce enough to be your primary oxidizer. Also 2 step bromine will keep usually show a drop in bromine over time until you oxidize again.

 

In a one step or 2 step system, yes. In a correctly set up 3 step system with a good floater such as the Pentair the bromine levels will stay fairly constant. It can take a lot of trial and error to get the floater adjustment right. When I had a bromine stand along spa many moons ago it took me about 2 months to get the floater adjusted so my bromine levels were constant.

Oddly mine is a CD ozonator and still per this experiment does not oxidize enough to negate the need for manual shock in my 2-step

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10 minutes ago, waterbear said:

In theory but not in actual practice. Most ozone generators in tubs are UV and not corona discharge and don't really produce enough to be your primary oxidizer. Also 2 step bromine will keep usually show a drop in bromine over time until you oxidize again.

 

In a one step or 2 step system, yes. In a correctly set up 3 step system with a good floater such as the Pentair the bromine levels will stay fairly constant. It can take a lot of trial and error to get the floater adjustment right. When I had a bromine stand along spa many moons ago it took me about 2 months to get the floater adjusted so my bromine levels were constant.

What causes bromine in a 2-step system to dissipate without use?  Is it just natural decay of the chemical? Eating away at germs even though tub not in use?  I suspect some combo of both. 

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16 minutes ago, mscdman said:

Oddly mine is a CD ozonator and still per this experiment does not oxidize enough to negate the need for manual shock in my 2-step

In a 2 step system it probably won't. Does your CD have a drying chamber? If it does not then ozone production will drop as the humidity of the air goes up. IMHO, a CD unit without a drying chamber is basically useless.

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Alot of new tubs are using CD ozonators, even some older ones, but in the big picture it is a drop in the bucket. The purpose of the ozone is not to generate bromine, it is to oxidize chloramines, which are much more reactive than bromide. To do what you are talking would take a much larger unit and injection system. But that would create it's own set of problems. 

You are trying to cook a pizza in a tanning bed.

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19 minutes ago, mscdman said:

What causes bromine in a 2-step system to dissipate without use?

same thing that causes it to drop after you shock and the level goes way high. If the level stayed constant there would be no need to keep adding sanitizer, even when the spa  or pool is not in use. the only way to maintain a constant level is by a constant addition of your chosen sanitizer. this is why salt systems, peristaltic pumps, and feeder systems are used.

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28 minutes ago, RDspaguy said:

Alot of new tubs are using CD ozonators, even some older ones, but in the big picture it is a drop in the bucket. The purpose of the ozone is not to generate bromine, it is to oxidize chloramines, which are much more reactive than bromide. To do what you are talking would take a much larger unit and injection system. But that would create it's own set of problems. 

You are trying to cook a pizza in a tanning bed.

To clarify, I’m not “trying” to generate bromine using my CD ozonator.  I was just curious if it would.  And I’m finding it doesn’t.  Which to be honest I’m happy about. I don’t like the idea of not having control over the level of bromine generated.  Which is why I’m liking this 2-step bromine using bleach method.  I can theoretically generate the exact amount of bromine I need using a specified amount of bleach.  Of course that theory is also currently being tested for feasibility in my system.   If it doesn’t work I’ll have to

go to 3-step but I am optimistic it will

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Update:  I have a nifty excel sheet I’ve been tracking bromine levels and decay.   So far it’s looking like about a 4-5ppm per day decay/loss of bromine with no use and around 6-8 ppm drop with a  tub use on that day.   This is with a CD ozonator and no floater.  I currently use the tub every other day so what I’m trying to determine now is what level I need to pump up the bromine to after use so that it’s at 5-6ppm during my use days.  If I’m doing my math right I need the levels AFTER use to be 11ppm.  Then it should be right at 5-6ppm when I get in the day after the skip day.    According to the pool calculator 1.5 tsp of my 82% dichlor/15% bromide mixture for my tub size after use should do it.  I may add 2tsp though to be safe after every use.   
 

For you cheapos like me this is only $.20 cents of chemicals per use or about $2.50 a month.   That’s pretty cheap chemical wise vs bromine tablets if you ask me. In reality it will be cheaper than that because I’m planning to switch to Bleach as soon as CYA levels are in range

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  • 2 weeks later...

Incidentally, are there any hardware or shell or cover problems if the bromine levels are not constant like I have?  Meaning it’s 10+ppm when I’m not using it then is low when using then back up 10+?

Otherwise rather than adding oxidizer after every use (every other day ish) I’d have to add daily inbetween uses 

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I think you are overthinking it. If your cover is closed then no new contaminants are entering the water. Ozone can't get 100%, but if you sanitize after use then close it up the ozone should be fine to keep it fresh for several days at least. 

I personally add chlorine after each use and rely on my ozone to get rid of it before I open up again, and .5ppm is my goal at time of use. 

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17 minutes ago, RDspaguy said:

I think you are overthinking it. If your cover is closed then no new contaminants are entering the water. Ozone can't get 100%, but if you sanitize after use then close it up the ozone should be fine to keep it fresh for several days at least. 

I personally add chlorine after each use and rely on my ozone to get rid of it before I open up again, and .5ppm is my goal at time of use. 

What do you typically raise it to after use when you sanitize (in ppm)?  And how long between uses?

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I add 1 tsp plus 1/2 to 1 tsp dichlor per user after use on a 400 gallon or so spa. That should be enough to land me in the 3ppm zone, but since I will get immediate oxidation and the chlorine combining to form chloramines it would be difficult to actually read that in time. 

I have an 8 year old so mine saw frequent heavy use.

I also use nature2 (silver ion) as well as ozone. And drain every 3 months and replace my nature2.

I don't smell chemicals, have ph issues, get strange rashes or itchy skin, or use mps. If it gets a bit murky I will hit it hard (1/2-1 cup) with liquid chlorine (12%). This happens if I spill a drink, one of the dogs jumps in, or my son is in and out with playtime in the yard. 

I will also mention that these amounts are in a range because I don't use a measuring device, so it is actually a bit of dichlor poured into the cap that looks about right, and a few splashes of liquid from the jug. 🙄 Yep. After all, it's just my tub. Not like it's a paying customer or anything.😉

That should drive @waterbearbatshit crazy.🤪

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14 minutes ago, RDspaguy said:

I add 1 tsp plus 1/2 to 1 tsp dichlor per user after use on a 400 gallon or so spa. That should be enough to land me in the 3ppm zone, but since I will get immediate oxidation and the chlorine combining to form chloramines it would be difficult to actually read that in time. 

I have an 8 year old so mine saw frequent heavy use.

I also use nature2 (silver ion) as well as ozone. And drain every 3 months and replace my nature2.

I don't smell chemicals, have ph issues, get strange rashes or itchy skin, or use mps. If it gets a bit murky I will hit it hard (1/2-1 cup) with liquid chlorine (12%). This happens if I spill a drink, one of the dogs jumps in, or my son is in and out with playtime in the yard. 

I will also mention that these amounts are in a range because I don't use a measuring device, so it is actually a bit of dichlor poured into the cap that looks about right, and a few splashes of liquid from the jug. 🙄 Yep. After all, it's just my tub. Not like it's a paying customer or anything.😉

That should drive @waterbearbatshit crazy.🤪

Sweet.  Do you use your hot tub typically daily or how many times a week?

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