The filtration system should allow for multiple complete turnovers of the water. The flow rate should be adjusted to allow for one turnover every six to eight hours. This allows up to three to four turnovers over a 24-hour period. For pool owners concerned with energy efficiency, a variable-speed pump (VSP) adjusted to a low speed during the night can keep the water moving and filtering.
Filter maintenance
An important, yet, neglected routine is filter maintenance. Each pool season should begin with a clean filter and periodic assessments of its performance throughout the season. Too often, filters will only be cleaned upon encountering cloudy water. Cloudy water, not caused by inadequate sanitization or improper balance, might be due to an underperforming or overly soiled filter. A quick examination of the filter pressure gauge reading above 137 kPa (20 psi) or low flow coming from the returns can be indicators of a filter needing service.
Simply rinsing a cartridge filter or backwashing a sand filter may leave behind more complex organic or mineral waste products. When to clean them can often depend on the type of filter or certain treatments that have been performed recently. Each filter type comes with unique challenges. Sand filters struggle more with tinier particles and might need additional help with filter aids, such as charged cellulose or diatomaceous earth (DE), which can sit atop the sand bed to better capture debris. This filter media may also develop channels or cracks running through the sand bed, allowing unfiltered water to pass through.
Cartridge filters might be able to capture smaller debris compared to sand, but it might need more cleaning or replacement after significant events. Dead algae and clarifier treatments often clog up these filters quickly. It is a good practice to have a second set of fresh cartridges to replace soiled ones while they are being cleaned.
Choosing the right type of cleaner will help when rinsing is not enough. If the buildup is mostly comprised of waste from heavy use, such as organic material or body oils, an alkaline formula with detergents and surfactants is preferred. Accumulated contaminants can also be region-specific. Pools in a calcium-rich water region or with a higher concentration of metals will need an acidic cleaner to neutralize these minerals. Keeping the filter healthy will go a long way in maintaining clean and clear water. If the problem is not alleviated by a clean filter, the issue might be mechanical due to cracked laterals or manifolds.
Coagulants and flocculants
Cloudy water in pools forms due to the accumulation of microscopic contaminants which are too small for the filter to collect. In recreational water, these contaminants usually have negative charges. Debris remains in colloidal suspension, where the similar charges combined repel each other so the particulates cannot settle.
