Once a bromine pool, always bromine ?

#1
My new outdoor pool went into service on March 16th with bromine as the sanitizer. I've been getting advice from others to switch to chlorine. I like the bromine water and I am reluctant to switch. To do so means draining the pool or use sodium thiosulfate to neutralize the bromine. If not done, any chlorine introduced will only reactivate the bromine "in the bank". However, since bromine is not UV stabilized will it not deteriorate in short time if I don't add any more? If the bromine is so "ever lasting", why do I have to keep adding more? The "once a bromine pool, always a bromine pool" seems to be flawed. Otherwise, using chlorine to reactivate the bromine over and over may prove to make bromine less costly than it appears. Any comments on this will be appreciated.
 

JVTrain

TFP Expert
Feb 3, 2014
5,080
Central Minnesota
#3
Once bromine, always bromine is certainly true. When bromine is depleted by sunlight or organics, it reverts to bromide ions. These bromide ions remain in the pool. As soon as a strong oxidizer is added (bleach, MPS, etc.) bromide is preferentially converted to bromine, immediately consuming the oxidizer added. You can maintain a bromine pool or spa once you have a bromide bank with any oxidizer you choose and it will still be a bromine pool. Bromine tablets are used because they are convenient. These tablets do also contain DMH which partially stabilizes bromine but doesn't do it very well. It also prevents bromine/bromide from eventually dissipating from the pool. If you were to only treat your pool with bleach for an extended period of time, eventually the bromide would outgas and you could treat as a chlorine pool. How long that would take would depend on how much DMH and bromide bank is in the pool.

For indoor pools and spas, bromine is a valid alternative to chlorine. For outdoor pools, bromine is an inferior option purely from a long term cost perspective.
 
OP
OP
CactusPool
Jan 19, 2017
10
Bullhead City, AZ
#4
By adding potassium monopersulfate to oxidize on a regular basis, the bromine is reactivated. Thus, the need to add more bromine is minimal. Using bromine is a less costly sanitizer than chlorine once the "bromine bank" is established, especially in a pool where the temperature will exceed 85 degrees Fahrenheit.
 

JVTrain

TFP Expert
Feb 3, 2014
5,080
Central Minnesota
#5
By adding potassium monopersulfate to oxidize on a regular basis, the bromine is reactivated. Thus, the need to add more bromine is minimal. Using bromine is a less costly sanitizer than chlorine once the "bromine bank" is established, especially in a pool where the temperature will exceed 85 degrees Fahrenheit.
This is simply not true for an outdoor pool. Bromine's CYA analog, dimethylhydantoin (DMH), only marginally protects bromine from UV light. Much less than CYA protects chlorine from UV light. Daily bromine losses to UV will be higher than chlorine in any outdoor pool.

Bromine VS Clorine

MPS is likely the most expensive way to convert bromide bank to active bromine. Bleach is much cheaper.

Do you have any data that supports pool water temperature induced differences in bromine and chlorine decay?