By Connie Sue Centrella
Today there is great acceptance to a wide variety of aquatic play features, including everything from waterslides and lazy rivers to activity pools, mushroom sprays, splash pads and wave pools. The tremendous popularity of waterparks with unique interactive water features has even sparked interest from residential pool owners. When it comes to size, these play features can be scaled back not only for smaller public pool installations, but also for residential applications.
These innovative aquatic features help remove the fear of water that young bathers sometimes have, as the shallow water, bubbling actions and spray features offer comfort and reassurance; however, they can also present new challenges and risk factors when it comes to maintenance and water quality concerns.
Understanding contamination hazards
Due to shallow water and active misters and sprayers that are common with aquatic play centres, there is a constant need for adequate disinfection, which must be continually monitored. As a result, contamination risks increase dramatically, making it critical for pool professionals to have a complete understanding of the complexities surrounding recreational water illnesses (RWIs).
In the public sector, health regulators are updating their guidelines to call attention to higher contamination probabilities. One important insertion into health codes is the implementation of secondary sanitation. The recommended level for disinfectants such as free available chlorine is two to four parts per million (ppm); however, with higher bather loads, free chlorine combines rapidly. Therefore, oxidation must take place at a faster rate. For this reason, a supplemental sanitizer is now recommended.
Ozone and ultraviolet (UV) disinfection systems have gained acceptance as additional means to eliminating chloramines and fighting RWIs. Controllers and automatic chemical feed systems, in conjunction with oxidation reduction potential (ORP) metering, are also proven safeguards in fighting contamination. In this case, ORP probes are installed on the return side of the filtration system to measure chlorine activity (the ratio of oxidation/reduction), which is expressed in millivolts (mV). As ORP is influenced by pH, the operator must take precautions to ensure the probes are calibrated and cleaned during routine maintenance. It is also advisable to take manual readings throughout the day to effectively monitor free available chlorine and pH.
How’s the water supply?
Most aquatic play features are installed in shallow water or in zero-depth entry pools. As a result, splash out can cause an increased demand for replacement water; therefore, it is important for operators to test the local water supply, as makeup water directly influences sanitization and water balance parameters.
Water chemistry for aquatic play features requires testing the five factors of water balance using the Langelier Saturation Index (LSI). This includes measuring the water’s pH, alkalinity (AT), calcium hardness, temperature and total dissolved solids (TDS). When these factors are calculated under the parameters of -.03 to +.03 on the index scale, the disinfection process is optimized.
These balancing factors are influenced by bather waste, disinfections, source water, airborne debris, aeration and evaporation. A low saturation index can cause corrosion of pool surfaces, equipment damage and bather’s eyes to burn, while a high saturation index can cause scale to form on pool surfaces and within the circulation system. This makes it vital for pool operators to understand the parameters of water balance to reduce the need of premature interior resurfacing and equipment replacement.