I follow the 3-step system for my bromine spa using 10% sodium hypochlorite for my oxidizer. The one thing I am a little unclear on is shocking. Is there a specific bromine level I am aiming for with the shock?
Question about shocking bromine
- Thread starter hmls
- Start date
- Jun 22, 2014
- 52,078
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Thanks. I have a hard time getting it that high though even after dumping in 8-10 oz of the 10%.
Generally when there's a problem maintaining the sanitizer level in a spa it means that it's due for a water change. How old is the water in your spa?
I don't have a problem maintaining the sanitizer level. It's not being used very much right now, and even though I don't check on it at much as I should, there is always bromine when I check it. It's just that I don't get to 20 ppm Br when shocking trying to shock it with the amount of 10% sodium hypochlorite that is supposed to do that. Even going well over the calculated amount. I have a 400 gal spa, and I understand Br = 2.25 x FC. So to get to 20 ppm Br, I would use about 9 ppm FC in the pool calculator, right? The calculator says to add 4.6 oz of 10% to go from 0 to 9 ppm of FC. I put in way more and never get close to 20 ppm Br.
Water is about 2 months old, but the same thing happened when it was new.
I do have an ozonator. Not sure if that changes anything.
I'm resurrecting this thread because I'm really hoping someone has some insight. I am still wondering why adding 10% sodium hypochlorite in the amounts given to me by PoolMath does not seem to result in the expected rise in Br. I just refilled the spa as follows:
1. Purge with Aqua Clarity. 12 oz for my 400 gal spa.
2. Drain and refill. Bit of a mishap here so ended up with roughly 1/2 softened water, 1/2 not.
3. CH measured 70 ppm after the refill so I added 5.3 oz by weight of Clorox calcium hardness increaser to bring it up to 175 ppm.
4. pH was 8+ so added dry acid to bring it down to 7.4.
5. Added 2 oz by weight of Leisure Time sodium bromide.
6. Added a little less than 4 oz of 10% pool chlorine which, per PoolMath, should have brought Br up to 15 ppm. Not even close. I tested after running the jets a bit and it was 1.25 ppm.
7. Chucked another 6 oz of chlorine in and got 8.75 ppm Br.
(Don't know if it matters, but the water was 65-70 degrees at this point.)
Does anyone have any idea what is going on here? I am crazy frustrated because it makes no sense. The spa was thoroughly purged with Ahhsome when new, has been purged on every refill with Aqua Clarity, and gets 2 oz of Aqua Clarity every week. I don't have any trouble maintaining normal Br levels, only getting shock levels. We have tabs in a floater and I usually add 1/2 oz chlorine after we use the tub. The spa is a Sundance Chelsee with ClearRay.
1. Purge with Aqua Clarity. 12 oz for my 400 gal spa.
2. Drain and refill. Bit of a mishap here so ended up with roughly 1/2 softened water, 1/2 not.
3. CH measured 70 ppm after the refill so I added 5.3 oz by weight of Clorox calcium hardness increaser to bring it up to 175 ppm.
4. pH was 8+ so added dry acid to bring it down to 7.4.
5. Added 2 oz by weight of Leisure Time sodium bromide.
6. Added a little less than 4 oz of 10% pool chlorine which, per PoolMath, should have brought Br up to 15 ppm. Not even close. I tested after running the jets a bit and it was 1.25 ppm.
7. Chucked another 6 oz of chlorine in and got 8.75 ppm Br.
(Don't know if it matters, but the water was 65-70 degrees at this point.)
Does anyone have any idea what is going on here? I am crazy frustrated because it makes no sense. The spa was thoroughly purged with Ahhsome when new, has been purged on every refill with Aqua Clarity, and gets 2 oz of Aqua Clarity every week. I don't have any trouble maintaining normal Br levels, only getting shock levels. We have tabs in a floater and I usually add 1/2 oz chlorine after we use the tub. The spa is a Sundance Chelsee with ClearRay.
Mercuric acid seems to be preferred over dry acid, but I'd guess same as @JamesW, maybe CC. Also, I'd consider the possibility your CHL has degraded and is not 10%.
When I started I think I put pencil to paper and used the bleach to dose a measured amount of distilled water and computed actual CHL %. But now I'm lazier (hard to imagine
), and base my adjustment on before and after adding when test numbers fail to meet expectations.Why would mercuric acid be preferred?Mercuric acid seems to be preferred over dry acid, but I'd guess same as @JamesW, maybe CC. Also, I'd consider the possibility your CHL has degraded and is not 10%.
When I started I think I put pencil to paper and used the bleach to dose a measured amount of distilled water and computed actual CHL %. But now I'm lazier (hard to imagine
I'm not sure how to test for CC. I have the Taylor K-2106 kit. Also, this is completely fresh water. No one has been in it.
How quickly does chlorine degrade?
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Get reagent R-0003 and add 5 drops after the solution goes colorless and see if it goes back to pink and then titrate back to colorless.
OK. Would you mind explaining why though? From what I read, CC comes from bather waste and no one has been in the tub. I'm not sure I understand how this relates to Br either.
Either the chlorine is bad or it is getting used up by something or it is locking up with something.
The CC test will see if it is locking up with something which is common with bromine.
Most people think that you won't get CCs with bromine, but they are actually very common.
The CC test will see if it is locking up with something which is common with bromine.
Most people think that you won't get CCs with bromine, but they are actually very common.
I thought that seemed wrong! Was too lazy to find the right word. Is there some reason it is preferred? I know I had a reason for going with dry acid, but I don't really remember now. I think it seemed safer to handle or something.
So yeah, mercuric ---> muriatic (dilute sulphuric acid), sorry.
Try googling "what is the lifespan of chlorine" for specifics?
Try googling "what is the lifespan of chlorine" for specifics?
I'm batting 0...
Wish I could say I forgot the question mark, but forgot my brain!
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