Our Full Guide on How To Backwash a Swimming Pool Filter
Backwashing your pool filter is a vital maintenance task that keeps your pool water clean and your filtration system running efficiently. By reversing the water flow through your filter, this flushes out trapped debris and dirt, ensuring that your pool stays crystal clear. Regular backwashing extends the life of your pool filter, improves circulation, and reduces the need for more intensive cleaning.
How To Backwash a Pool?
Backwashing your pool filter is a simple yet crucial process that removes accumulated debris from the filter media, helping to maintain the filter’s performance. This procedure is essential for preventing blockages that can strain your filtration system and reduce water flow. By regularly backwashing, you ensure that your pool’s filtration system operates at peak efficiency, which contributes to consistent water quality and minimizes the likelihood of algae growth or other water quality issues.
What is Backwashing a Pool?
- Definition: Backwashing is a method used to clean your pool filter by reversing the water flow, forcing out the accumulated dirt and debris.
- Purpose: It helps maintain the filter’s effectiveness by removing contaminants that clog the system.
- Benefits:
- Enhances water clarity.
- Improves overall pool circulation.
- Extends the lifespan of the pool filter.
- Reduces the frequency of manual cleaning.
How to Backwash Different Types of Pool Filters
How To Backwash a Sand Filter
- Turn off the pool pump: Before you begin the backwashing process, ensure the pool pump is completely turned off. Operating the filter valve while the pump is on can damage the system and compromise the filter’s effectiveness.
- Set the valve to “Backwash”: Locate the multiport valve on your sand filter and turn it to the “Backwash” setting. This position reverses the water flow through the filter, flushing out the trapped dirt and debris.
- Turn on the pump: Restart the pump and allow it to run in the backwash setting for 2-3 minutes. Monitor the sight glass or the water flow if you don’t have a sight glass. Continue until the water runs clear, indicating that the filter is clean.
- Turn off the pump again: After backwashing, turn off the pump to stop the flow of water. This step is crucial before moving the valve to the next setting to avoid damage.
- Set the valve to “Rinse”: Turn the valve to the “Rinse” position. This step helps to settle the sand in the filter and remove any remaining debris, preventing it from returning to the pool.
- Run the pump for 1-2 minutes: With the valve in the “Rinse” setting, turn the pump back on for 1-2 minutes. This process clears out any residual debris and ensures the filter is properly reset.
- Turn off the pump and set the valve back to “Filter”: Once rinsing is complete, turn off the pump again and switch the valve back to the “Filter” setting. This is the standard operating position for your sand filter.
- Restart the pump and resume normal operation: Finally, turn the pump back on to return to regular filtration. Check the pressure gauge to ensure it has returned to normal levels, indicating that the backwashing process was successful.
How To Backwash a DE Filter
- Switch off the pump: Begin by turning off the pool pump to prevent any damage to the filtration system. Working on a DE filter with the pump running can lead to complications and safety hazards.
- Turn the valve to “Backwash”: Locate the multiport valve or push-pull valve on your DE filter and switch it to the “Backwash” setting. This will reverse the flow of water, flushing out the diatomaceous earth (DE) and trapped debris from the filter.
- Restart the pump: Turn the pump back on and let it run in the backwash setting. Observe the sight glass or backwash hose, allowing the pump to run until the water turns clear. This typically takes 2-3 minutes. If your DE filter has a bump handle, you may need to “bump” the filter to dislodge any stubborn debris.
- Turn off the pump and set the valve to “Filter” briefly: After the initial backwash, turn off the pump and switch the valve back to the “Filter” position. This helps redistribute any remaining DE in the filter.
- Switch the valve back to “Backwash”: Repeat the backwash process by turning the valve back to “Backwash” and running the pump for another 1-2 minutes. This double backwashing ensures a thorough cleaning of the filter.
- Turn off the pump and return the valve to the “Filter” position: Once you’ve completed the backwash cycle, turn off the pump and set the valve back to the “Filter” position. This prepares your system for the addition of new DE powder.
- Add DE powder: Using a scoop or similar tool, add the recommended amount of DE powder to your skimmer while the pump is running. The standard dosage is typically around 1-2 pounds per 10 square feet of filter area. Adding DE helps to coat the filter grids, ensuring efficient filtration.
- Restart the pump for normal filtration: With the DE powder added, allow the pump to run continuously to resume normal pool filtration. Monitor the pressure gauge and ensure it reads within the normal range.
How To Backwash a Pool With a Cartridge Filter
Cartridge filters generally don’t require backwashing. Instead, they need periodic cleaning by removing the cartridge and rinsing it with a garden hose. For maintenance, you should inspect the cartridge every few weeks and replace it when it shows signs of wear or damage. Regular cleaning will keep your pool water clear and the filter functioning efficiently.
How Often Should You Backwash Your Pool?
| Filter Type | Backwash Frequency | Considerations |
| Sand Filter | Every 1-2 weeks | More frequent if the pool sees heavy use or after storms. |
| DE Filter | Every 4-6 weeks, or when pressure rises 8-10 psi above normal | Follow up with DE powder addition. |
| Cartridge Filter | Not applicable (clean cartridge instead every 4-6 weeks) | Replace the cartridge as needed for optimal performance. |
Troubleshooting Common Backwashing Issues
Rinsing and Dirt Passing Back into The Pool
Problem: Cloudy water after backwashing
- Cause: Incomplete rinsing of the filter after backwashing can lead to cloudy water, as fine particles and debris may still be present in the system.
- Solution: After completing the backwash cycle, it’s crucial to set the multiport valve to “Rinse” and run the pump for 1-2 minutes. This step helps settle the filter media (sand or DE) and flush out any remaining particles. Ensure you perform this step every time you backwash.
Problem: Dirt flows back into the pool
- Cause: If dirt and debris re-enter the pool after backwashing, it’s often due to a malfunctioning valve, worn-out gaskets, or an improper filter setting.
- Solution: First, check the multiport valve and ensure it’s set correctly. Inspect the valve gasket for signs of wear or damage and replace it if necessary. Additionally, ensure the filter is seated properly and that all connections are secure. If the issue persists, consider servicing the filter to check for internal damage.
Problem: Inadequate pressure during backwashing
- Cause: Low pressure during the backwash cycle can result from a clogged filter, insufficient pump power, or an air leak in the system.
- Solution: Start by inspecting the filter media for clogs or blockages that might reduce water flow. Clean or replace the filter media if necessary. Check for air leaks by inspecting the pump lid and all connections, ensuring they are airtight. If the pump is undersized for your filter, you may need to upgrade to a more powerful model to achieve effective backwashing.
Problem: Filter media escaping into the pool
- Cause: If sand or DE powder is escaping into the pool, it usually indicates a problem with the filter’s internal components, such as broken laterals in a sand filter or torn grids in a DE filter.
- Solution: Inspect the filter internals for any signs of damage. In a sand filter, check the laterals for cracks or breaks and replace them if necessary. For a DE filter, examine the grids for tears or holes and repair or replace any damaged components. Regular maintenance and inspections can help prevent these issues.
Learn How to Clean and Maintain Your Swimming Pool.
Where Does Backwash Pool Water Go?
Backwash water typically flows into a designated waste area, such as a drain or sewer. It’s essential to ensure that the disposal method complies with local environmental regulations, as improper disposal can harm the ecosystem. You might consider using a backwash hose to direct the water to a safe location, or consult your local guidelines to ensure environmentally responsible practices.
Explore The Ultimate Guide to Swimming Pool Maintenance.
How To Backwash Pool Filter - Frequently Asked Questions
- How much DE powder is needed after backwashing?
Generally, you should add 1-2 pounds of DE powder per 10 square feet of filter area after each backwash. - How long should the backwash cycle last?
The backwash cycle typically lasts 2-3 minutes or until the water runs clear in the sight glass. - What signs indicate the need to backwash?
A pressure rise of 8-10 psi above normal operating pressure is a key indicator that backwashing is needed. - Can backwashing affect pool chemistry?
Yes, backwashing can lower your pool’s water level and dilute the chemicals, requiring adjustments afterward. - Where does the backwash water go?
Backwash water is usually directed to a waste drain or sewer line. Ensure it’s disposed of according to local regulations. - Is it necessary to adjust pool chemicals after backwashing?
Yes, you should test and adjust your pool chemicals after backwashing to maintain balanced water chemistry.
