Optimal Pool Water Balance
Pool water quality is affected by the level of pH, which is affected by alkalinity. Pool water pH levels that are too high can cloud the water or create scaly deposits, but low pH levels allow for pool equipment and surfaces to become etched and corroded. Water balance for pools essentially means to bring into balance chemically, the most important factors being the pool pH, total alkalinity (TA) and calcium hardness (CH) levels.
Association of Pool & Spa Professionals (APSP) Pool Maintenance Technicians use the langelier saturation index or LSI, to check the overall state of water. The LSI is a valuable tool that has been used in the pool industry for decades and helps determine if water is generally corrosive, prone to scaling or in a good neutral state.
Typical Sequence of Swimming Pool Events
|LSI= +.1 (76°)||7.5||90||300||<1000|
Targets: Water is neither corrosive nor scale forming.
- Initial Pool Fill. Pool is filled with fresh water from the city that contains minerals (i.e. salt, calcium, magnesium, other metals, etc.).
- The water is balanced to meet pool industry parameters. The objective is to balance pH, calcium, and chlorination components to achieve optimal TDS and alkalinity relationships.
- As evaporation takes pure H20, leaving behind the minerals water with more minerals is added to the pool.
- Swimmers enter the pool carrying “bather waste.” APSP guidelines typically recommend a regular water replacement program based on number of daily bathers. As new water is added it affects the water chemical balance.
- Disinfectant is added to the pool to keep the water clean increasing the risk of high Disinfection By-Products (DBPs).
- Algaecides are added to the pool to keep the water clear of algae.
- Minerals, DBPs, waste and other metals overwhelm the water.
- The pool is drained.
|Sodium Hypochlorite (Liquid Chlorine) →||Salt|
(Cal Hypo) →
|Trichlor (Tabs) →||Cyanuric Acid|
|Dichlor (Granular) →||Cyanuric Acid|
|Salt Water Generators →||Salt|
Cyanuric Acid is one of the most problematic build ups and is the subject of much controversy
Note: Events 3-6 increase the pool's TDS which if not handled properly result in high Total Dissolved Solids (TDS) and chloramines (combined chlorines) of a corrosive nature with repercussions. Calcium hardness scale develops on equipment, filters, plumbing, and pool surfaces. CYA build up over 100ppm impacts on Cryptosporidium remediation and on Total Alkalinity tests. Testing Interferences increase (with proportionate accuracy decrease) due to dealing outside of recommended (controllable) parameters.
PoolPreserver obviates pool draining and refill conventionalities by cleaning pools with its Treat-in-Place technologies. These technologies address the above issues and effectively "refresh & reboot" the pool's water, enabling simpler and more reliable pool water balance.