Is Your Hayward Cartridge Filter Not Filtering Properly? Here’s What to Check
A sparkling, crystal-clear pool is every pool owner’s goal—but when your Hayward cartridge filter stops working properly, that dream quickly fades into murky water. If you’ve noticed cloudy pool water, poor circulation, or unusual pressure readings, your filtration system may be compromised.
Hayward is known for its high-quality pool equipment, and cartridge filters are a popular choice due to their efficiency, ease of maintenance, and eco-friendliness. However, like all equipment, they require regular care and occasional troubleshooting.
In this guide, we’ll walk you through the most common reasons your Hayward cartridge filter might not be filtering properly—and what steps to take before calling in a professional.
Understanding How Hayward Cartridge Filters Work
Before diagnosing problems, it’s important to understand how your Hayward cartridge filter functions.
A cartridge filter works by pushing pool water through a pleated polyester filter element that traps dirt, debris, and microscopic contaminants. The clean water is then returned to the pool. Over time, the filter can become clogged, damaged, or inefficient—leading to issues in water clarity and flow.
Clogging
Pressure issues
Improper installation
Poor water chemistry
Wear and tear on internal parts
1. Check for Clogged or Dirty Filter Cartridges
Symptoms:
Cloudy water
Decreased water flow
High pressure on the gauge
The most common issue is a dirty or clogged filter cartridge. If debris builds up in the pleats of the cartridge, water cannot pass through effectively, reducing filtration performance.
Solution:
Remove the cartridge from the housing.
Rinse it thoroughly with a garden hose, using a nozzle to get into the pleats.
For deep cleaning, soak the cartridge overnight in a filter cleaner or diluted muriatic acid solution (as per manufacturer instructions).
Rinse thoroughly before reinstalling.
 Pro Tip: Clean the cartridge every 4–6 weeks during heavy use. Every year or as needed, depending on wear and performance, replace it.
Keep your pool sparkling with the help of reliable Hayward cartridge pool filters.
2. Inspect the Pressure Gauge
Symptoms:
Unusually high or low PSI readings
Filter runs too frequently
Water not circulating properly
Your Hayward filter is equipped with a pressure gauge that indicates the system’s performance. A high-pressure reading usually means the filter is dirty or blocked. A low-pressure reading may indicate a problem with the pump, air leaks, or water flow.
Solution:
Clean or replace the filter cartridge.
Look for obstructions in the plumbing lines, pump basket, or skimmer.
Inspect for air leaks in the suction line, especially around pump lid o-rings or fittings.
 Maintenance Tip: Note the pressure reading after installing a clean cartridge. This becomes your “baseline.” Add 8–10 PSI to this number as your indicator for the next cleaning.
3. Examine for Damaged or Worn Cartridges
Symptoms:
Debris bypassing the filter
Uneven water clarity
Filter looks intact but still underperforms
If your cartridge is clean but still not filtering properly, it may be damaged internally. Tears, collapsed pleats, or a broken core allow debris to pass through into the pool.
Solution:
Carefully examine the cartridge element for cracks, holes, or flattened pleats.
Check the end caps and inner core for structural damage.
Replace the cartridge if any signs of wear are present.
Note: Even high-end cartridges lose efficiency after extended use, typically after 12–24 months depending on pool usage and maintenance.
4. Assess Water Chemistry Balance
Symptoms:
Algae growth despite filtration
Cloudy or green water
Filter clogs faster than usual
Unbalanced pool chemistry can overwhelm your filter system. High levels of calcium, metals, or algae spores can clog the cartridge prematurely or even cause scaling.
Solution:
Test your water for:
pH (7.4–7.6)
Chlorine (1–3 ppm)
Total alkalinity (80–120 ppm)
Calcium hardness (200–400 ppm)
Shock the pool if necessary to eliminate contaminants.
Backwash or clean the filter after shocking or heavy chemical treatment.
 Best Practice: Always maintain balanced chemistry to reduce strain on your filtration system.
5. Check for Improper Filter Installation
Symptoms:
Leaking filter housing
Cartridge doesn’t sit securely
Pressure fluctuations
If the cartridge isn’t seated properly, water can bypass the filter entirely or cause uneven pressure. Likewise, a misaligned or cross-threaded lid can result in leaks and reduced performance.
Solution:
Turn off the system and open the housing.
Ensure the cartridge is centered and properly aligned.
Lubricate the O-rings with a silicone-based lubricant.
Tighten the lid evenly, using manufacturer guidelines for torque or hand pressure.
 Install Tip: Always refer to your Hayward manual when reassembling the filter to avoid damaging threads or seals.
6. Inspect the Pool Pump and Plumbing System
Symptoms:
Low water flow despite clean filter
Pump not priming
Filter pressure won’t stabilize
Your cartridge filter relies on your pool pump to deliver consistent water flow. If your pump is undersized, malfunctioning, or struggling with suction issues, the filter won’t work effectively—even if it’s clean.
Solution:
Check the pump basket and impeller for blockages.
Ensure proper pump sizing relative to the filter (GPM vs. filter flow rate).
Look for leaks or air bubbles in the return lines.
Replace or service the pump if needed.
Reminder: Undersized pumps and oversized filters can cause inefficiency and unfiltered water.
7. Consider Environmental Factors
Symptoms:
Filter clogs quickly after cleaning
Excess debris in the pool
Algae and organics overwhelming the system
Sometimes, the issue isn’t the filter—it’s the environment around your pool. Falling leaves, heavy bather loads, nearby construction, or high pollen levels can fill your filter faster than normal.
Solution:
Use a pool cover when the pool is not in use.
Skim and vacuum the pool regularly.
Clean the cartridge more frequently during high-debris periods.
Trim nearby vegetation or trees contributing organic matter.
 Eco Tip: A pool-friendly landscape and regular surface maintenance greatly extend filter life.
When to Replace Your Hayward Cartridge Filter
Even with proper care, no filter lasts forever. If your Hayward cartridge filter continues to underperform after all the steps above, it might be time for a full replacement—especially if:
You’ve used the same cartridge for 2+ years
You notice deep creases, collapsed pleats, or structural damage
Your water clarity doesn’t improve even after thorough cleaning
 Recommended Replacement Frequency: Every 1 to 2 years, depending on usage, water chemistry, and maintenance habits.
Keep Your Pool Clear with Proactive Filter Care
A Hayward cartridge filter is a powerful tool in maintaining pool hygiene, but it’s only as good as the care it receives. By proactively checking for clogs, pressure changes, wear and tear, and pump-related issues, you can avoid murky water and enjoy a crystal-clear pool all season long.
