Oh, you backwashed last week? Great. I’m sure your old filter media applauded politely before going back to letting junk slip right through. Most pool owners treat their filter media like a family heirloom, something to hold on to forever. Unfortunately, that’s not how pool maintenance works. If your sand, cartridge, or DE grids are years past their prime, you’re basically just circulating bad water in a loop.
Let’s break this down and talk about the mistakes people make when they think their filter media will last forever.
Mistake #1: Believing Backwashing is Magic
Backwashing is great for flushing out loose dirt, but it does not restore your old filter media to factory-new performance. Sand gets rounded over time and loses its sharp edges that trap particles. Cartridge fibers fray and get clogged. DE grids get worn thin. At some point, the material is simply worn out and cannot filter properly.
Simple fix:
- For sand filters: Replace sand every 3 to 5 years.
- For cartridge filters: Replace cartridges every 2 to 3 years.
- For DE filters: Replace grids every 7 to 10 years, or sooner if damaged.
Ignoring these timelines just means your pump is working harder for worse results.
Mistake #2: Thinking Cloudy Water is a Chemical Problem
If your water still looks off even after balancing chemicals, it might not be the water chemistry at all. Old filter media cannot trap fine debris, so everything just keeps circulating. That means more sanitizer is burned up trying to fight the junk your filter should have removed.
Simple fix:
- If you have to shock more often than usual, check your filter media age.
- Use your filter’s maintenance history, not your neighbor’s guesswork.
Mistake #3: Trusting That “It Still Works” Means “It Works Well”
Yes, water still flows through your old filter media. That does not mean it is doing the job right. Think of it like a coffee filter that has been used 200 times. It still lets liquid through, but it is not doing much filtering.
Simple fix:
- Set a replacement schedule and stick to it.
- Keep a log of the last time you changed the media.
Mistake #4: Ignoring Pressure Gauge Changes
If your filter pressure runs high even after cleaning or backwashing, your media is likely clogged beyond saving. The pump is straining, your energy bill is creeping up, and your water is slowly getting worse.
Simple fix:
- Replace the media before the pressure problem damages the pump.
Mistake #5: Believing Pool Stores Will Remind You
No, they will not. Pool stores are not your personal reminder service. If you do not track your own filter media age, no one else will.
Simple fix:
- Write the replacement date directly on the filter tank with a marker.
- Set a calendar reminder for 2 to 5 years depending on your filter type.
Why Old Filter Media is a Bigger Deal Than You Think
When filter media ages out, it stops removing the microscopic debris that makes pool water look dull and uninviting. Worse, it can allow bacteria and algae spores to pass through unchecked. That means you will spend more on chemicals and cleaning while getting worse results.
Old filter media also causes:
- Shorter pump lifespan due to higher strain.
- Increased energy costs.
- Frustration because you keep treating symptoms, not the root cause.
Replace your old filter media before you waste another season fighting your water. Your pool will look better, feel better, and cost less to maintain when your filter actually does its job.
