Brominated pools tend to exhibit different characteristics than those of pools using traditional chlorine sanitation. Pool operators need to know the nuances of working with bromine in order to maximize oxidizer efficiency, improve the overall swimmer experience, and minimize the associated maintenance.
No more breakpoint
One advantage bromine has over more traditional programs is that it retains active efficiency after reacting with nitrogenous swimmer wastes. Unlike chloramines, bromamines are disinfectants with activity that rivals that of either free chlorine or free bromine. In addition, bromamines do not produce the noxious odors and associated eye and skin irritation attributed to chloramines. Therefore, “breakpoint” sanitation is unnecessary in bromine pools, as bromamines maintain oxidizing activity in the water while retaining aesthetically pleasing qualities.
Though bromamines retain oxidizing activity in the water, and do not produce the infamous “chlorine” odors associated with chloramines, frequent oxidation for a bromine pool is still important. There are two reasons for this:
First, supplemental oxidation facilitates the regeneration process of the bromide ion (Br-). Once spent by oxidizing organic material or inactivating microorganisms, the majority of active bromine reverts to bromide. This regenerative process is unique to bromine in typical swimming pool water, and is how spent bromine is reactivated into its disinfecting form (OBr-).
Therefore, frequent oxidation by either a chlorine or a non-chlorine shock such as potassium monopersulfate is necessary to convert the bromide.
Second, oxidation is still required to break down some of the more complex organic wastes introduced by bathers. Generally, bromine is less powerful than some of its oxidizer counterparts, so it’s important that a user continue to shock frequently to rid the water of organic wastes that can exhaust sanitizer and give the water a dull appearance.
Higher pH tolerance
Bromine dissociates at a higher pH range than chlorine. What this means is that it remains in its active form at higher pH, yielding nearly twice the active efficiency of chlorine at a pH of 7.5, and more than two and a half times the active efficiency at a pH of 7.8.
This is one reason why bromine is more common in spas, due to the natural tendency of spas to operate at a higher pH level as a result of the volatility of carbon dioxide when running the jets.
In addition to its oxidative properties, bromine exhibits superior algaecidal characteristics. Studies have documented that free chlorine can behave as an algaestat at a concentration of 0.2 ppm, meaning that it will control algae and prevent growth. However, bromine behaves as an algaecide at a concentration of 0.2 ppm, meaning that it can kill algae to reduce the overall algal population.
Due to these algaecidal properties, bromine pools that have recurring issues of resistant or mustard algae typically operate more efficiently and with less trouble through a full season. It’s a helpful option for those customers who are having difficulty eliminating their algae issues.
Bromine is a great option for indoor pools due to the activity and volatility resistance of the bromamine byproducts. The reason bromine pools tend to have reduced odor is due to the lower vapor pressure properties of bromamines. The benefits of this behavior include reduced respiratory irritation to swimmers and less corrosivity to the ventilation system.
However, ventilation systems are still critically important for indoor pools, even ones using bromine. Ventilation systems manage indoor humidity to help limit heat loss from the pool. They also serve as an
exhaust for other gasses that volatilize due to the oxidation process of organic wastes by supplemental oxidation.
Since bromine cannot be stabilized against the degrading effects of certain bands of UV light, as chlorine can, it has typically been discounted for use in outdoor pools. However, there are methods for managing bromine to mitigate these degrading effects of UV.
Implementation of a continual feed system helps users manage their bromine degradation. Studies have shown that operating a pool at the lower end of the recommended sanitizer range reduces the amount of bromine subject to degradation: The less bromine you keep in the pool, the less is degraded by sunlight.
The half life of bromine is approximately one hour, which means that it will lose about half its oxidizing strength for every hour it is exposed to external sunlight. Therefore, a pool operating at 3 ppm will lose 1.5 ppm of bromine; as opposed to a pool operating at 5 ppm, which will lose 2.5 ppm of bromine over the same 60-minute time period.
Adjusting your feeder to maintain the lower end of the range will minimize the amount of bromine that feeds into the pool. In addition, weekly feeder top-off practices have resulted in a high rate of success.
Keeping a full feeder facilitates a more constant feed rate; as tablets erode, the amount of bromine fed to the pool is reduced. Maintaining a full feeder gives an operator greater control over the pool and thus allows for a minimal loss of sanitizer to UV degradation.
Balance is important for swimming pools, whether it’s proper water balance to protect the swimmers, surface and equipment; or balancing the benefits of pleasant swimming experiences and easy maintenance against the costs.