I have a 13,500 gallon above ground pool. We use 1 inch bromine tabs and weekly shock from pool logic. I don't have a test kit yet, but my question is can I use bleach as a shock. I understand that to convert to a chlorine pool I probably need to drain. We have had a horrible algae problem that shock seems to clear up, but I would like to use the TFP method. Don't want to drain the pool and i guess the bromine tabs are fine to use but the bleach and ph method would be easier.
Bromine pool, use chlorine as shock?
- Thread starter Max1030
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Well, I can't answer you question, but this thread from 2010 has a lot of useful information.
Do a search on bromine here and you will find more
Welcome to TFP
Do a search on bromine here and you will find more
Welcome to TFP
You sure can use bleach as shock. The bleach will oxidize the bromine that has been converted to bromide and turn it back into bromine. This thread which is aimed at spa usage of bromine is the best resource you have here: How do I use Bromine in my spa (or pool)
The saying is: Once a bromine spa (pool), always a bromine spa (pool). Unless you drain the water, you'll have a bromine pool. Here's the consequences of that:
1. Bromine is unprotected from sunlight/UV break down. There is no CYA equivalent for bromine. CYA normally protects chlorine from sunlight, making it more efficient for outdoor pool use. Your chemical costs will be higher with a bromine pool due to sunlight degradation of bromine.
2. The bleach only converts bromide to bromine. It will do that until all of the bromide has been converted. You likely have A LOT of bromine/bromide in the pool so a large bromine bank to convert. You won't ever have actual free chlorine in your pool for very long as it will be consumed oxidizing bromide. You will have plenty of bromine after you shock (oxidize) with bleach.
3. As I said, you'll have a bromine pool until you drain and refill. You'll have to drain most of the water or all of it to convert to a chlorine pool.
Reading through that thread will teach you a lot about how bromine works. It's worth the time.
The saying is: Once a bromine spa (pool), always a bromine spa (pool). Unless you drain the water, you'll have a bromine pool. Here's the consequences of that:
1. Bromine is unprotected from sunlight/UV break down. There is no CYA equivalent for bromine. CYA normally protects chlorine from sunlight, making it more efficient for outdoor pool use. Your chemical costs will be higher with a bromine pool due to sunlight degradation of bromine.
2. The bleach only converts bromide to bromine. It will do that until all of the bromide has been converted. You likely have A LOT of bromine/bromide in the pool so a large bromine bank to convert. You won't ever have actual free chlorine in your pool for very long as it will be consumed oxidizing bromide. You will have plenty of bromine after you shock (oxidize) with bleach.
3. As I said, you'll have a bromine pool until you drain and refill. You'll have to drain most of the water or all of it to convert to a chlorine pool.
Reading through that thread will teach you a lot about how bromine works. It's worth the time.
In other words can I stop using bromine and shock and just start testing and using bleach.
No. The bleach will just convert bromine that has been converted to bromide and turn it back into bromine, using up the bleach in the process. The only way to switch to a chlorine pool is to drain and refill. You'll have to drain most of the water or all of it to convert to a chlorine pool.
You can just switch to oxidizing with bleach but it will remain a bromine pool. You're going to lose significant amounts of bromine to sunlight each day. So the answer is yes but it's costly. Much more costly than an actual chlorine pool would be. I would wager that each day just to sunlight if you're losing for example 10 ppm of free bromine, if you switched to a chlorine pool, you'd be losing 2-3 ppm free chlorine when protected by CYA. And without protection from CYA, your bromine levels will be high when you add bleach but drop quickly each day, depending on amount of sun. It might be more manageable if you have an opaque cover to use.
It's doable, but I'd suggest swapping to a chlorine/CYA pool for a better long term experience.
So the only way to do that is to drain? I'm really trying to avoid draining. I don't mind using the bromine if they are effective, but this year it seemed to not help. Looks like shock and bromine is all I can do.
I think that it's worthwhile to try using only bleach for a while to see if it works for you. Bromine does not lose as much to sunlight as unstabilized chlorine because the higher pKa means that there's less hypobromite than hypochlorite at the same pH. It's the hypochlorite or hypobromite that is primarily lost to sunlight. Continuous dosing would work better than periodic dosing. That way you can maintain a lower but steady bromine level. A peristaltic pump would be a good choice.
You could try using a salt system as that would give you a steady dose of chlorine/bromine. I have seen that work. The bromine level usually does not get very high, but the continuous gain and loss reaches an equilibrium. The cell will not last as long due to needing to run it at a higher percentage.
Note that most manufacturers don't recommend using their salt systems on bromine pools. Therefore, you're going outside their requirements and probably void the warranty if it should be necessary to make a claim and they know you're using it for a non-standard purpose.
Also, I have seen where the addition of cyanuric acid seemed to help maintain bromine levels. Although cyanuric acid does not bind to bromine, it might protect bromine at lower depths by making the water more opaque to UV. However, that's not a known fact.
Another complicating factor is the presence of dmh, which is the carrier chemical for the bromine tabs. Some bromine probably binds to dmh in the same way that chlorine binds to cyanuric acid. It might provide some sun protection and it probably reduces the effectiveness of the bromine. Fist, we don't know how much dmh is in the water. Although, we could estimate the amount from the total weight of tabs used. Second, we don't know the equilibrium constants for bromine-dmh. And third, we don't know if bromine bound to dmh retains any significant oxidizing or sanitizing capacity.
Long term, it would be better to drain and refill to get on a stabilized chlorine regimen.
You could try using a salt system as that would give you a steady dose of chlorine/bromine. I have seen that work. The bromine level usually does not get very high, but the continuous gain and loss reaches an equilibrium. The cell will not last as long due to needing to run it at a higher percentage.
Note that most manufacturers don't recommend using their salt systems on bromine pools. Therefore, you're going outside their requirements and probably void the warranty if it should be necessary to make a claim and they know you're using it for a non-standard purpose.
Also, I have seen where the addition of cyanuric acid seemed to help maintain bromine levels. Although cyanuric acid does not bind to bromine, it might protect bromine at lower depths by making the water more opaque to UV. However, that's not a known fact.
Another complicating factor is the presence of dmh, which is the carrier chemical for the bromine tabs. Some bromine probably binds to dmh in the same way that chlorine binds to cyanuric acid. It might provide some sun protection and it probably reduces the effectiveness of the bromine. Fist, we don't know how much dmh is in the water. Although, we could estimate the amount from the total weight of tabs used. Second, we don't know the equilibrium constants for bromine-dmh. And third, we don't know if bromine bound to dmh retains any significant oxidizing or sanitizing capacity.
Long term, it would be better to drain and refill to get on a stabilized chlorine regimen.
My advice to you is not to drain yet. First try to operate the pool ignoring that you have a bromine banc. Bromine tablets add DMH to the pool water and that acts like CYA in a chlorine pool. Measure how much you still have at the end of the day. Every pool is different and DMH is (for most of people) not possible to measure, but what matters is the dynamic of the sanitizer. If you still have the minimum amount of sanitizer at the end of the day, do not drain. If you find that you have to use much more and it is costly, than you may decide to drain the pool. Most of the chlorine pools use 2-3 ppm of chorine per day. 3ppm of chorine will generate 6ppm of bromine from the bromide bank. If you have still 2ppm of bromine at the end of the day, you are better off by not draining. I am operating o bromine pool and I need only 1ppm of chorine daily, but I have a low pressure UV-c germicidal lamp.