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Dolphin Pool & Spa

Inspecting and Replacing Pool Filter Media Each Spring

Thursday, April 30, 2026  ·  Your Happy Dolphin Pool & Spa Team

Pool technician inspecting filter media during spring pool opening

Images are AI generated and do not depict an actual pool or Dolphin Pool & Spa location.

Your pool filter is the hardest-working piece of equipment you own — quietly running hour after hour, pulling dirt, debris, algae, and fine particles out of your water all season long. But here's the thing: what's inside that filter matters just as much as the filter itself. If you're still running standard silica sand from five or more years ago, you may be filtering far less effectively than you think.

Spring is the perfect time to pop the lid, take a look at what's in there, and make a decision about whether it's time for a change. Here's what to look for — and what your upgrade options are.

1 Know Your Filter Type First

Before you inspect anything, it helps to know what kind of filter you're working with. There are three common types in residential pools:

Filter Type What's Inside Media Replacement?
Sand Filter Silica sand, ZeoSand, RubySand, or Micron1 Yes — every 3–7 years
Cartridge Filter Pleated polyester cartridge(s) Yes — every 1–3 years
DE Filter Diatomaceous earth powder on grids Finest filtration of the three — but DE powder must be re-added after every backwash, which is the ongoing hassle that makes many owners wish they had a sand filter

Sand filters are by far the most common in Minnesota residential pools, so we'll focus there — but the inspection tips below apply to all three types.

2 How to Inspect Your Filter Media

With a sand filter, you can do a quick visual inspection by removing the top valve or multiport head and looking down into the tank. You're checking for:

  • Channeling — grooves or tunnels carved through the sand where water bypasses filtration
  • Clumping or caking — sand that's hardened into solid chunks from oil and scale buildup
  • Mudballing — greasy, ball-shaped clumps that prevent proper backwashing
  • Cloudy water that won't clear — often a sign the sand is spent and no longer filtering fine particles
  • Sand in the pool — indicates broken laterals inside the filter that need replacement
  • Age — standard silica sand should be replaced every 3–5 years regardless of appearance

💡 Pro Tip: If you can't remember the last time your sand was changed, it's time. Most pool owners replace it far less often than they should — and wonder why their water stays cloudy even with proper chemistry.

3 Your Filter Media Options — and Why Upgrading Makes Sense

If you're changing your media this spring, you have better options than the same old silica sand. Here's how they compare:

Media Filters Down To Best For
Standard Silica Sand 20–40 microns Basic filtration — the baseline
ZeoSand 5 microns Clearer water, also reduces ammonia & chloramines
RubySand 3–5 microns Crystal-clear water, lasts longer than standard sand
Micron1 ⭐ 1 micron The ultimate upgrade — near DE-quality clarity in a sand filter

💡 Our Recommendation: Micron1

Micron1 filters down to just 1 micron — that's 20 to 40 times finer than standard sand. The result is visibly clearer water, a reduced chemical load, and less time spent troubleshooting cloudiness. If you're already pulling the media out, upgrading to Micron1 is one of the best investments you can make in your pool for the season. Ask us about it next time you stop in.

4 What a Sand Change Service Includes

Changing filter sand yourself is doable, but it's a messy job — old sand has to come out, the laterals need to be inspected, and the new media has to be packed in correctly to avoid channeling right from the start. Our professional sand change service takes care of all of it:

  • Remove and dispose of old media
  • Inspect laterals and standpipe for damage
  • Install your choice of new media
  • Reassemble and pressure-test the filter
  • Perform initial backwash cycle
  • Confirm proper flow and pressure readings

⚠️ Always Replace Your Laterals at the Same Time

This is one of the most important things we tell every customer doing a media change: replace the laterals while you're already in there. Years of chlorine exposure makes the plastic brittle, and the physical process of scooping out the old media — even when done carefully — almost always cracks one or more laterals. If you skip the lateral replacement and a cracked one lets sand pass through into your pool, you'll have to drain the filter, remove all the new media, replace the laterals, and refill the filter with fresh media all over again. That's two sand changes for the price of one mistake. Laterals are inexpensive. Do it once, do it right.

📋 Sand Change Service — $389.99 (labor only; media and laterals are additional depending on filter model). Give us a call to schedule yours this spring before the season gets busy.

5 Don't Forget Your Cartridge Filter

If you have a cartridge filter, spring is the time to pull the cartridges and give them a thorough inspection. Look for:

  • Tears, cracks, or holes in the pleated fabric
  • Collapsed or deformed end caps
  • Heavy calcium scale that won't soak off
  • Browning or graying that persists after cleaning
  • Pressure that spikes unusually fast after cleaning
  • Cartridges that are 3+ years old

A clean, intact cartridge filters down to about 10–15 microns. Once the fabric starts to break down, that number climbs fast. Bring your old cartridge in to the store and we can help you find the right replacement.

6 What to Check While You Have the Filter Open

While you've got the filter disassembled, take a few extra minutes to check these things:

  • O-rings and gaskets — replace if cracked, flat, or brittle
  • Multiport valve — check for cracks in the housing and smooth operation of all positions
  • Pressure gauge — if it reads 0 at startup or sticks, replace it (they're inexpensive)
  • Sight glass on multiport — should run clear during normal operation
  • Filter tank itself — look for cracks, UV damage, or separation at seams
  • Backwash hose — replace if cracked or stiff from winter storage

💡 Reminder: Your filter's normal operating pressure is whatever it reads right after a fresh backwash at the start of the season. Write that number down somewhere — it's your baseline. Time to backwash when pressure climbs 8–10 PSI above that number.

Ready to Upgrade Your Filtration?

We Carry Micron1, ZeoSand, RubySand & More.

Stop in and talk to us about what's right for your filter, or give us a call to schedule a professional sand change. We're here Mon–Thurs 8–5, Fri 8–6, and Sat 8–4.

Call Us Now — 763-542-9000
Dolphin Pool & Spa

Your Happy Dolphin Pool & Spa Team

3405 Hwy 169 N, Plymouth MN  ·  763-542-9000  ·  dolphinpool-spa.com