What is the filter’s role in water quality?
With good circulation in place, a pool ecosystem relies on proper filtration to remove debris and other contaminants from the water. The physical and biological processes occurring inside the filter increase the demand on the sanitizer and make it less efficient by performing activities outside of sanitization.
As the filter performs its primary job, the contaminants fill the empty space between media—whether they are pores in a cartridge or the space between granules of sand, glass, and diatomaceous earth (DE). This increases the media’s ability to filter smaller and smaller particles which improves clarity; however, flow inside begins to decrease as pressure within the system increases. Over time, the efficiency of the media is reduced, increasing the opportunity for biofilm growth within the filter. Certain micro-organisms can produce byproducts that increase the demand on a chlorine-based sanitizer.
Routine filter maintenance such as backwashing or rinsing cartridges will remove loose accumulations. Periodic chemical filter cleaning during the season removes the more difficult greases, oils, and scale that reduce filter effectiveness. Service technicians should be mindful not all filter cleaners work for every type of accumulation. Therefore, it is important to read labels and directions carefully before treatment.
Another method to increase chemical efficiency by keeping a clean filter is to incorporate products into weekly service that help reduce the filter load. Routine use of enzyme-based products can be an effective tool to help break down non-living organic accumulations in the filter media and provide longer filter cycles between cleanings. Most enzyme-based products also contain surfactants that not only help keep a filter clean, but also aid in other problematic areas of the pool as well.
Dealing with problematic areas
One of the more unsightly and most recognized sources of frustration that can lead to increased sanitizer usage is the formation of waterlines on the pool surface. Oils, greases, and other wastes enter the pool water from bathers and most float on the surface.
These nuisance contaminants mix with other debris that float and begin to accumulate on the pool walls, creating an unpleasant waterline that can also collect bacteria and algae. Brushing is the most effective way to break down these accumulations and get them back into the bulk solution of the pool before they cause a problem.
Other areas of the pool also provide favourable conditions for accumulations that can lead to larger issues. Dead spots are areas of the pool where circulation is poor due to a variety of reasons, such as the pool’s shape and structure, special features, and other in-pool accessories. For vinyl pools, certain seam locations can also provide a favourable surface for accumulations to develop.
These areas should be brushed at least once a week to keep surfaces clean. The use of water tension modifiers can also help keep these areas clean. Certain algaecides and most enzyme-based products contain surfactants that modify water tension, helping to pull debris off surfaces and back into the water where it can be removed by the filter or broken down further by treatment products.
Common areas to watch for buildup of debris, algae, or biofilm growth include:
- Light niche;
- Behind drop-in steps;
- Behind ladders;
- Sharp corners;
- Underneath ladder treads; and
- Fountain or spa spillovers.
