Building a Bromide Bank with Sodium Bromide granules

[cschnurr]

I have always sanitized my hot tub using the 3-step system described in
How do I use Bromine in my spa (or pool)?

I used liquid 'Rendezvous Enhance' (35% Sodium Bromide)
The instructions were clear that the initial dose was @ 125ml/1000l water.
I rarely used the weekly dose of 30ml/1000l and I maintained bromine tablets in the feeder, and after each use I used 'Rendevous Activator' (potassium monopersulfate, MPS).

My pool store is no longer able to get the Rendezvous Enhance/Activator.
They recommended 'Spalife EZ Brom' (15% Sodium Bromide granules) and 'Spalife Shock' (Chlorine Free Oxidzer granules, contains MPS)

I just changed the water and I am trying to determine how much EZ Brom I need to build my bromine bank.
The instructions state 6g, (1/2 tbsp 7.5ml) per 1000l water repeated until residual of 3 to 5 ppm.
and superchlorinate at 25g (2 tbsp, 30ml) per 1000l water as required.

I'm questioning the dosages because the 35% Enhance required 125ml/1000ml, I'd expect the 15% EZ Brom to be close to 300ml/1000ml.
Which would require 20 repeats of 7.5ml.

Is the difference explainable if the liquid Enhance % could be %volume, and EZ Brom granules %weight, or am I missing something?

I thought the Rendezvous product might be discontinued because of Canadian restrictions on the use Sodium Bromide with MPS.
However these products continue to use Sodium Bromide and MPS activator.

 

[Mdragger88]

Not sure - lets ask @JoyfulNoise
& @JamesW

 

[JoyfulNoise]

Can you show the product label or list the amounts of the dichlor and sodium bromide?

It would appear from the MSDS that the product is mostly dichlor with NaBr added. Based on the dosing rate of about 6 grams per 1000L of water that should yield a bromine level of about 6ppm with each dose. But you’re also adding about 6ppm of cyanuric acid each time. The cyanuric acid does not affect the bromine but it will slow the oxidation process that converts the bromide to bromine (chlorine in the dichlor gets reduced to chloride as it activates the bromine). Your bromide bank of 30ppm will be established with about 5 to 6 additions of the EZ Brom stuff.

MPS is really very slow at activating bromine. It’s used more as a non-chlorine oxidizer to breakdown bather waste. And it can be confusing to most test kits as it will interfere with total bromine readings until it is used up.

Do you ever just use liquid chlorine to activate the bromine? That’s what you would need to do to not add anymore CYA to the tub and get fast activation if the bromine.

Honestly, bromine hot tubs are a pain in the rear to take care of. I’d much rather use chlorine as it’s much simpler easy to dose.

 

[cschnurr]

Thanks for the reply.
The Spalife EZ Brom label says 47% Dichlor and 15% Sodium Bromide.


The Spalife Shock label says Chlorine Free Oxidizer... For Bromine or Chlorine Sanitizers. It does not have chemical ingredients except in the First Aid warning it states that it contains MPS, no % listed.

If 5-6 additions of EZ Brom = 30-35g of CYA. I'll have 25-28ppm (1250 l tub) after building my bank. I'll be careful and monitor ongoing to prevent ongoing CYA additions, but I don't think I'm should be overly concerned.

A month ago I went to the PS to get a replacement for Rendezvous Activator Granules and the recommended Spalife Shock. Both activate the Sodium Bromide already in the tub using MPS, so that shouldn't have been any real change.

Yesterday, after a drain/refill, the PS told me that the Rendezvous Enhance used to generate the bromide bank was also no longer available. They recommended that I didn't need the Sodium Bromide and only needed the Spalife Shock. No chlorine or Bromine except whatever the feeder provides. Does this make sense?

She stated that if I wanted Bromine, it was available in the EZ Brom product. I bought some but sensed a definite lack of knowledge on their part. I know enough not to rely on PS chemists, that's why I submitted this post.

I've always used the 3 step Bromine in my hot tub. The spa sales guys recommended Bromine, I just learned how to do it, never had any problems so never considered Chlorine.
We typically use the tub a only couple times a week, and use MPS (initially Rendezvous Activator, now Spalife Shock) after each tub.

Are you recommend that I change over to Chlorine, eliminating the Sodium Bromide, or to continue using Sodium Bromide and activate using liquid Chlorine?
I had already poured some Enhance from my last bottle into the tub before I went to the pool store so I'll consider switching from from Sodium Bromide to chlorine at the next refill.

I think I'll just crush up some bromide tablets to create my bank, return the EZ Brom for a refund, and continue activating with Spalife Shock to deplete my Bromine chemicals, and wait until next refill to switch to Chlorine in the spring. I have a chlorine pool with a SWG, and occasionally use 10% liquid chlorine. Liquid chlorine would work well in the spring to fall. But in winter, I'd likely use liquid chlorine after refilling, then use either MPS or Dichlor granules (5% bleach might be more manageable).

 

[Mdragger88]

I believe he was saying both-
You can use liquid chlorine to reactivate your bromine bank instead of using any mps.
In my opinion mps is a pain in multiple ways. Ymmv.
You can also switch to chlorine only (dichlor then bleach method) after your next refill & ditch the bromine all together. Mps isn’t absolutely necessary in either a chlorine or bromine tub & it has its own issues as mentioned previously so I choose not to use it.
Many folks alternate sanitation methods with each refill depending upon how they are going to use the tub in their upcoming season of life. The advantage of bromine is that you can get away with less frequent dosing than with a manually chlorinated tub but it has its drawbacks/complications as you’re dealing with now. Some people are also sensitive to the smell & the bromine itself.
Using a swcg takes some of the frequent dosing troubles away from a chlorine tub & is the easiest solution for many with little complication.
From my understanding, The Dichlor in that product should activate the bromine making that product sort of an “all in one solution” if you will, until your bank is established. I could be wrong about this.. Hopefully Matt will elaborate there.
After your bank is established Then you can choose to use mps or bleach to reactivate it as needed.
I’m not sure that crushing the tablets you have is a good choice- again, let’s wait for @JoyfulNoise on that one.

 

[cschnurr]

Thanks Matt. So far I have liked using liquid Bromine. I’m just trying to understand the difference between the liquid and granule sources of Sodium Bromide.

 

[JamesW]

Establishing a bromide bank is vastly overrated.

It is really not necessary because the chlorine will just stay as chlorine until you get some bromide in the water, but even a few ppm of bromide begins to be effective.

I would not worry about establishing a bromide bank.

 

[JoyfulNoise]

Also note that using tablets to build up the bromide bank is fine but they are acidic and they will reduce pH and TA. So while you use them at a higher rate to get that bromide bank, please carefully watch TA and pH and adjust as-needed. If you can detect a measurable drop in TA for each tablet that you consume then you might go ahead and add some baking soda to compensate for the amount of TA you expect to be used up. Your pH might run a bit high doing that, but it really shouldn’t be an issue unless your water has very high levels of calcium hardness.

 

[Mdragger88]

Also note that using tablets to build up the bromide bank is fine but they are acidic and they will reduce pH and TA. So while you use them at a higher rate to get that bromide bank, please carefully watch TA and pH and adjust as-needed. If you can detect a measurable drop in TA for each tablet that you consume then you might go ahead and add some baking soda to compensate for the amount of TA you expect to be used up. Your pH might run a bit high doing that, but it really shouldn’t be an issue unless your water has very high levels of calcium hardness.

I can only assume this happens faster if the tablets are crushed- which is why I think I recall reading not to crush them correct?

 

[JamesW]

People should not crush tablets as this is dangerous and it will be difficult to control the chemistry.

 

[JoyfulNoise]

I can only assume this happens faster if the tablets are crushed- which is why I think I recall reading not to crush them correct?

Correct.

You can crush tablets and use the like you would dichlor powder but the resulting dissolution will cause the pH to drop quite a bit. It’s not really the best thing to do but people do it … (and then they wonder why their heaters corrode away).

Notice I said “can” and not “should” … just because you can do something doesn’t mean it’s a good idea . For example, I CAN give @JamesW my banking and credit card info for safe keeping … but we all know he would book a trip to Fiji faster than Bill Elliot on the Talladega NASCAR track …

 

[JamesW]

You definitely do not want to be hammering away on bromine tablets with a hammer with pieces of bromine tabs flying everywhere and bromine tablet dust billowing up into the air.

 

[Mdragger88]

Correct.

You can crush tablets and use the like you would dichlor powder but the resulting dissolution will cause the pH to drop quite a bit. It’s not really the best thing to do but people do it … (and then they wonder why their heaters corrode away).

Notice I said “can” and not “should” … just because you can do something doesn’t mean it’s a good idea . For example, I CAN give @JamesW my banking and credit card info for safe keeping … but we all know he would book a trip to Fiji faster than Bill Elliot on the Talladega NASCAR track …

Bill Elliot! You’re showing your age now!

 

[JoyfulNoise]

You definitely do not want to be hammering away on bromine tablets with a hammer with pieces of bromine tabs flying everywhere and bromine tablet dust billowing up into the air.

That’s why you put them in a ziplock bag BEFORE you start hammering them silly … someone has obviously never made veal scallopini before …

 

[JoyfulNoise]

Bill Elliot! You’re showing your age now!

I do remember when the rocks were still soft

 

[JamesW]

For example, I CAN give @JamesW my banking and credit card info for safe keeping … but we all know he would book a trip to Fiji faster than Bill Elliot on the Talladega NASCAR track …

Trip booked.

I will send you a postcard.

 

[JamesW]

Also, you should change your bank account password.

"Password123" is not a secure password.

 

[JoyfulNoise]

I’ll add an exclamation mark ️ to the end, that should help

 

[JamesW]

https://www.amazon.com/Leisure-Time-Sodium-Bromide-Pack/dp/B082B6VBPD/

 

[cschnurr]

Thanks for all the input, you've made me much more comfortable.

James, the Leisure Time bromide looks like exactly what I thought I'd need (and its available in Canada on Amazon.ca)
But knowing that I don't need to be overly concerned about building the bank because it essentially will build itself, I don't feel a need to over think this.

I'll just use the EZ Brom I have, monitor TA and pH carefully until my Bromine stabilizes and monitor CYA if I add any more.

Since I only need 30-35g of EZ Brom to build my bank, my 800g container should last me for over 20 water changes.
That's over 5 years! Does that seem right????
Matt, I looked at your calculation that 6g of EZ Brom produces 6ppm of Bromide per 1000 litres of water
I've forgotten my Chemistry lessons from 40 years ago, so I'll trust yours.
I suspect my confusion is buried in the relative molecular weights and chemical equations (I used to know that stuff)

I'll use chlorine, or MSP to activate/oxidize after each use and occasional shock.

James, while you have the card handy, just order and ship me a Spa SWG and my bromine problems are solved.