Sand Pool Filters: Backwashing, Sand Replacement, Pressure Problems & Common Issues

Sand pool filters are one of the most durable and low-maintenance filtration systems used in residential pools. They filter water by trapping debris inside specially graded pool filter sand. While sand filters are reliable, most problems come from dirty sand, improper backwashing, worn multiport valves, and pressure issues. This guide answers the most common sand filter questions homeowners ask.

Quick Sand Filter Diagnostics Checklist

You may have a sand filter problem if you notice:

• High or low filter pressure

• Weak return flow

• Cloudy or dusty water

• Sand blowing into the pool

• Water leaking from the backwash line

• Multiport valve hard to turn

• Pool won’t stay clean despite good chemistry

How Often Should I Backwash My Sand Filter?

You should backwash your sand filter when:

• Pressure rises 8–10 PSI above clean pressure

• Water flow slows down

• Pool begins to look cloudy

For most pools, this means:

• Every 1–4 weeks during swim season

• After heavy storms or algae treatments

How Often Do You Change the Sand in a Pool Filter?

Most sand filters need new sand:

• Every 3–5 years

• Sooner if:

  • Sand is clumped or calcified

  • Pool stays cloudy despite proper backwashing

  • Pressure stays high even after backwashing

Old sand becomes rounded and loses its ability to trap debris.

Why Is Sand Blowing Back Into My Pool?

Sand returning to the pool is usually caused by:

• Broken laterals inside the filter

• Cracked standpipe

• Incorrect sand grade

• Damaged multiport valve spider gasket

• Excessive pump pressure

Sand in the pool should be addressed immediately to prevent line and equipment damage.

Is a Sand Filter Better Than a Cartridge Filter?

Sand Filter Pros

• ✅ Low maintenance

• ✅ Durable

• ✅ Inexpensive media

• ✅ Handles heavy debris well

• ✅ Easy backwashing

Sand Filter Cons

• ❌ Slightly less water clarity than cartridge

• ❌ Water wasted during backwash

• ❌ Sand must be replaced every few years

Why Is My Sand Filter Pressure Too High or Too Low?

High Pressure Causes

• Dirty sand

• Calcified sand

• Backwash valve stuck

• Return line blockage

Low Pressure Causes

• Pump losing prime

• Air leak on suction side

• Clogged skimmer or pump basket

• Open backwash valve

• Broken impeller

Both conditions severely affect circulation and must be corrected quickly.

Step-By-Step: Proper Way to Backwash a Sand Filter

1. Turn off the pump

2. Set valve to Backwash

3. Turn pump on for 2–3 minutes

4. Turn pump off

5. Set valve to Rinse

6. Turn pump on for 30–60 seconds

7. Turn pump off

8. Set valve to Filter

9. Restart pump and check pressure

Most Common Sand Filter Problems

• Worn spider gasket in multiport valve

• Cracked standpipe

• Broken laterals

• Calcified sand

• Leaking backwash lines

• Valve handle stuck or seized

When Should You Replace Sand Instead of Backwashing?

You should replace your sand if:

• Backwashing does not reduce pressure

• Pool remains cloudy despite clean chemistry

• Sand clumps together

• Calcium buildup is present

• Sand is over 5 years old

Replacement restores full filtration efficiency.

Sand Filter vs Cartridge Filter (Quick Comparison)

Sand Filter:

• ✅ Low maintenance

• ✅ Cheap media

• ✅ Long tank life

• ✅ Handles debris well

• ❌ Slightly lower clarity

• ❌ Water lost during backwash

Cartridge Filter:

• ✅ Superior water clarity

• ✅ No backwashing

• ❌ Requires manual cleaning

• ❌ Cartridge replacement cost

When to Call a Professional for Sand Filter Problems

Call a pool professional if:

• Sand is blowing back into the pool

• Pressure stays high after backwashing

• Valve leaks continuously

• Laterals are damaged

• You need sand replacement

• Pool won’t clear

Professional Sand Filter Service in Peoria, AZ

If you’re in Peoria or the West Valley, Triton Pools provides full sand filter services:

• Backwash valve repair

• Sand replacement

• Pressure diagnostics

• Leak repair

• Full circulation inspections

• Equipment upgrades

Schedule your sand filter service with Triton Pools today.

FAQ: Sand Pool Filters

How long does sand last in a pool filter?
Most pool filter sand lasts 3–5 years before replacement is needed.

Can I use regular sand in my pool filter?
No. Only #20 silica pool filter sand should be used.

Why is my pool cloudy after backwashing?
This may indicate worn sand, broken laterals, or improper rinse cycle.

How long should I backwash a sand filter?
Typically 2–3 minutes or until the water in the sight glass is clear.

Can I convert a sand filter to glass media?
Yes. Filter glass media lasts longer and improves clarity.