When it comes to pool filtration, one of the most common questions pool owners have is whether the pool filter is supposed to run continuously or only for set periods of time. There are pros and cons to both continuous filtration and intermittent filtration, so understanding the differences is important in order to make the right choice for your pool.
The Purpose of Pool Filtration
The main job of the pool filter is to remove contaminants from the water by circulating it through the filter media (sand, DE, cartridges, etc). As water passes through the filter, debris and particulates are captured, leaving cleaner water to go back into the pool. Some key contaminants the filter removes include:
- Dirt
- Pollen, leaves, and other organic debris
- Dust
- Bacteria
- Algae spores
- Insects/bugs
- Oils, suntan lotions, and other chemicals introduced by swimmers
By continuously running the filter pump and pulling water through the filter, these contaminants can be constantly removed to keep water clarity high. Intermittent filtration runs on a schedule, filtering for set periods of time throughout the day.
Continuous Filtration
Continuous filtration, as the name suggests, involves running the pool filter pump 24 hours a day, 7 days a week without turning it off. This provides maximum filtration for the pool at all times. There are some key advantages to continuous running:
- Consistent removal of contaminants – With the filter always running, it is constantly pulling debris, bacteria, chemicals, and particulates out of the water, providing the cleanest water possible.
- Prevents algae growth – The filter removes and traps algae spores. Running it continuously keeps these spores under control before they can take hold and create an algae bloom.
- Easier maintenance – Keeping the filter pump on prevents debris from settling in the pump and plumbing where it can ultimately cause clogs or damage. Continuous operation means less system maintenance overall.
- May extend equipment life – By preventing settling of dirt and debris during inactive periods, continuous operation may reduce wear on pool equipment like pumps and filters over time.
The biggest disadvantage of continuous operation is higher energy usage since the system runs 24/7. But modern energy-efficient pumps and motors have brought the costs down compared to years past. Continuous filtration is recommended for pools that get heavy use and require maximum water quality. It is also ideal for pools that are more susceptible to algae growth if the filter cycle is interrupted.
Intermittent Filtration
Intermittent filtration involves running the pool filter on a timed schedule, such as:
- 8 hours per day
- 12 hours on, 12 hours off
- Overnight operation only
This mode saves energy compared to continuous running. It may be adequate for pools with lighter use. There are some downsides to consider:
- Potential for reduced water quality – With the filter off part of the day, contaminants can accumulate in the water, making it cloudy with debris and allowing algae and bacteria growth.
- Algae growth – Off periods allow algae spores to take hold unimpeded since they are not being constantly filtered out.
- Settling of debris – When the pump is off, debris, dirt, and particles settle in the system, increasing the risk of clogs and wear on equipment.
- Equipment issues – Repeated cycling on and off can place extra wear on the pump and filter.
Intermittent operation may be sufficient for very clean pools with minimal use, lower temperatures, and low organic debris loads. But continuous 24/7 operation is generally recommended for most residential and commercial pools.
Guidelines for Continuous Filtration
Running your pool filter continuously provides the highest level of filtration, but it also requires following some guidelines to prevent problems:
- Use an appropriately sized pump and filter for 24/7 use and the size of your pool.
- Maintain proper water chemistry and chemical balance – this prevents scale buildup and corrosion.
- Periodically inspect and clean the filter per manufacturer recommendations to prevent flow restrictions.
- Check for leaks and ensure proper water level is maintained in the pool.
- Have a qualified pool professional do periodic inspections of the pump, filter, and systems.
- Replace the filter media like DE or sand as needed per manufacturer specifications.
Following these guidelines allows continuous operation to provide maximum benefit without causing increased maintenance or equipment issues down the road.
Pool Size Considerations
Pool size is one factor to consider when determining whether continuous or intermittent filtration is most appropriate:
| Pool Size | Recommended Filtration |
|---|---|
| Small pools up to 15,000 gallons | Intermittent, 6-8 hours per day |
| Medium pools 15,000 – 30,000 gallons | Intermittent or continuous |
| Large pools over 30,000 gallons | Continuous filtration recommended |
Larger pools have higher contaminant and bather loads, so they benefit more from continuous operation. Smaller pools may be able to achieve adequate water quality with intermittent cycles. Medium pools could use either effectively if sized properly.
Climate Differences
The climate where you live also impacts the recommended filtration time. Here are some general guidelines per climate:
| Climate | Recommended Filtration Time |
|---|---|
| Hot climates | 24/7 continuous operation |
| Warm climates | At least 12 hours per day |
| Cooler climates | 8-12 hours per day seasonally |
Warmer regions have higher contaminant loads from increased bather use, dust, pollen, etc. Colder areas may be able to filter less during closed pool seasons but should increase to daily operation as temperatures rise.
New Pool Installation Recommendations
For newly constructed pools, builders and service professionals generally recommend continuous 24/7 filtration for the first year of operation. Reasons include:
- New pools tend to have higher loads of construction debris that need filtering out.
- Helps ensure the plaster or finish cures properly when filters run continuously.
- Removes initial debris, dust and particulates from fill water.
- Helps prevent algae growth on pristine new surfaces.
After the first year, new pools may be able to switch to intermittent operation if water quality remains high. But continuous filtration is still a good idea for new pools that get heavy use and for those located in warmer climates.
Consider Backup Power
Using continuous filtration does come with the risk that power outages will halt filtration until electricity is restored. In climates where power failures are common, you may want to consider installing a backup power source like a generator or battery to keep the filter and pump running when the power goes out.
Key options include:
- Whole house generator – Natural gas or propane powered generators that can run central air, appliances, pool equipment, etc. during an outage.
- Portable generator – Gas or diesel powered portable generators that can be connected to run pool equipment only.
- Battery backup power – An inverter and battery bank that automatically runs the pool pump if electricity is cut off.
Though expensive, these can automatically restore filtration if electricity fails so water quality is unaffected in outages lasting up to several days.
Use a Timer for Intermittent Filtration
For pools running on intermittent filtration, using a timer ensures the filter pump runs on a consistent schedule. This provides effective filtration while saving energy on off-hours. Key tips on using a pump timer include:
- Choose a digital timer offering at least 2 on/off cycles per day.
- Set the timer to run when electricity rates are lowest to save money.
- Make sure the timer turns on before peak pool use hours.
- Don’t reduce runtimes too much – this can impact water clarity.
- Adjust intervals seasonally based on pool use and climate.
- Allow extra runtimes on weekends in summer when pool use increases.
With some trial and adjustment, an automated timer allows tailoring intermittent operation for your pool’s conditions and saving substantially on electricity costs.
Variable Speed Pumps
As energy-saving options have improved, many pool owners are switching to variable speed pumps for filtration. These pumps can run at different speeds as needed:
- Low speed for continuous operation to remove light debris and prevent algae.
- Higher speed during peak use times and when vacuuming or cleaning.
- Lowest speed when pool is closed for winter or not in use.
By adjusting speeds seasonally and for conditions, variable speed pumps provide maximum efficiency and cost savings while maintaining water quality. They allow continuous operation for cleaner water without the increased energy burden of single-speed pumps running 24/7.
Automation Systems
For ultimate convenience, pool automation systems can fully manage filtration on custom schedules, adjusting for seasonal changes, use patterns and events like parties. Automation allows settings like:
- Running overnight in winter at low speed.
- Increasing to 24 hour operation in summer.
- Boosting pump speeds on heavy use weekends.
- Reducing runtimes when on vacation.
With the ability to tweak settings from a smartphone, pool automation provides both convenience and optimal energy efficiency for filtration.
Conclusion
To keep pool water clean and clear, proper filtration is essential. While filters can run intermittently or continuously, most pools benefit from having the filter pump run 24 hours a day for maximum contaminant removal. Continuous operation prevents debris buildup, controls algae, and maintains water clarity at all times while helping extend equipment life. With today’s energy-efficient pumps and motors, the costs of running filters 24/7 are reasonable for most pool owners when balanced against the benefits of maximum water quality.
