Bromine level always zero

[rocket04]

I’m in Canada and got my hot tub going using a one step product. It took a while for the bank to build but then things were ok… for a while. But now I’ve noticed that I add product and when I test the next day my bromine is always at zero. I use the Taylor kit I have for my pool with the FAS-DPD, I just multiply FC result by 2.25. Which of course, lately I don’t need to bother doing since it’s always zero. Is sodium bromide like CYA for chlorine, where as it gets high you need more and more dichlor to keep the levels up? I never bothered changing to a floater because I wasn’t getting around to going to the pool store, I thought the only downside to continuing with my one step product was that it was needlessly expensive. Maybe I was mistaken?

[thecanadiran]

Have you tried shocking with bleach to activate the existing sodium bromide?

[rocket04]

On 12/21/2021 at 3:18 PM, thecanadiran said:

Have you tried shocking with bleach to activate the existing sodium bromide?

I hadn’t but I did do it a few times now. Still not sure things are normal given that I now got my floater and I have it open on setting 8 and my FC is still pretty low. But I’m going to monitor over the next few days and see.

[dlleno]

On 12/18/2021 at 7:55 AM, rocket04 said:

I’m in Canada and got my hot tub going using a one step product. It took a while for the bank to build but then things were ok… for a while. But now I’ve noticed that I add product and when I test the next day my bromine is always at zero. I use the Taylor kit I have for my pool with the FAS-DPD, I just multiply FC result by 2.25. Which of course, lately I don’t need to bother doing since it’s always zero. Is sodium bromide like CYA for chlorine, where as it gets high you need more and more dichlor to keep the levels up? I never bothered changing to a floater because I wasn’t getting around to going to the pool store, I thought the only downside to continuing with my one step product was that it was needlessly expensive. Maybe I was mistaken?

no, sodium bromide is not like CYA at all;  it is the bromide bank that is oxidized to produce bromine sanitizer. higher sodium bromide levels are not bad.  and even if your bromide bank is zero or very low -- when you add the one-step product your spa will be mostly chlorine (from the dichlor) and the FAS-DPD test will respond to the chlorine (sample will turn pink)

rising levels of CYA due to increasing use of dichlor is also relatively benign for bromine.  the conversion to bromine still happens very quickly per chem geek such that high CYA isn't a problem either for a bromine spa..

if you are experiencing disappearing bromine levels consider purging with ahh-some.  you could have biofilms in there chowing down on your sanitizer 

I happen to agree that the one-step product is expensive.  get bromide starters (granular or liquid) and then use dichlor for the oxidzer.  maintaining a bromine spa in this way is exactly the same as maintaining a chlorine spa except (in a bromine spa) the dichlor oxidizes the bromide bank into bromine sanitizer 

[waterbear]

19 hours ago, dlleno said:

when you add the one-step product your spa will be mostly chlorine (from the dichlor) and the FAS-DPD test will respond to the chlorine (sample will turn pink)

No, this is not true. The chlorine in the one step product will oxidize the bromide in the product and create bromine sanitizer.

 

19 hours ago, dlleno said:

get bromide starters (granular or liquid) and then use dichlor for the oxidzer

OP stated he is in Canada. Sodium Bromide is not available in Canada.

 

19 hours ago, dlleno said:

maintaining a bromine spa in this way is exactly the same as maintaining a chlorine spa

NO ,it is not. Parameters for bromine are different than parameters for chlorine. For example, bromamines are active sanitizers so bromine systems are only tested for total bromine and pH range is wider for bromine spas. Also, the effect of DMHD used in bromine tabs needs to be taken into consideration when 3 step bromine is used.

[waterbear]

On 12/18/2021 at 9:55 AM, rocket04 said:

and when I test the next day my bromine is always at zero

Your high sanitizer demand sounds like it might be a biofilm problem. When is the last time you purged your spa?

What are your thoughts @RDspaguyand @Ahhsomeguy?

[Ahhsomeguy]

I am not a huge fan of bromine and can share very little information regarding these posts.  I can wholly recommend that “rocket04” perform a plumbing purge.  He seems to be experiencing a rapid depletion of sanitizer and an effective plumbing purge will definitely help him.  

[dlleno]

3 hours ago, waterbear said:

No, this is not true. The chlorine in the one step product will oxidize the bromide in the product and create bromine sanitizer.

 

OP stated he is in Canada. Sodium Bromide is not available in Canada.

 

NO ,it is not. Parameters for bromine are different than parameters for chlorine. For example, bromamines are active sanitizers so bromine systems are only tested for total bromine and pH range is wider for bromine spas. Also, the effect of DMHD used in bromine tabs needs to be taken into consideration when 3 step bromine is used.

OK fair enough what I meant here is that regular addition of chlorine to a bromine spa,  With bromide bank present,  is the same motion and quantities used to manually add chlorine to a chlorine spa. 

 

In my experience,  the one step 85/15 granules do  result in  hypochlorous acid on the first application because of insufficient bromide  bank.  It's 85 percent dichlor and 15 percent sodium Bromide .  Using this product on a regular basis builds the bank gradually

 

[waterbear]

20 hours ago, dlleno said:

In my experience,  the one step 85/15 granules do  result in  hypochlorous acid on the first application because of insufficient bromide  bank

I am very interested in how you determine this since OTO (orthotolidine) , DPD (diethyl-p-phenyleneldiamine), FAS-DPD (ferrous ammonium sulfate / diethyl-p-phenyleneldiamine), and SYD (syringaldazine) cannot differentiate between chlorine, bromine,  iodine, nor MPS.

A bromide bank is NOT necessary if you are adding both sodium bromide and an oxidizer at the same time. In fact, this is how two step bromine works. The one step products just mix them together  so you do not need to dose with 2 products at the same time. Perhaps you should learn a bit more about the chemistry behind the use of  bromine in a hot tub.

If there is no bromide bank it means that you have to add sodium bromide and an oxidizer to create bromine sanitizer, once the bromide reserve is established then only the addition of an oxidizer is necessary to generate bromine sanitizer.