Pool filters get blamed for a whole lot of things they didn’t do.

Cloudy water? Must be the filter.

Weak circulation? Filter.

Dirt coming back into the pool? Definitely the filter.

Maybe.

But after more than 30 years around swimming pools, I can tell you that sometimes that poor filter is just standing there minding its own business while something else upstream is starving it half to death.

That’s what I dug into for this week’s Pool Gal Chronicles video — pool filters.

Sand, Cartridge or D.E. — They All Need One Thing

No matter which type of filter you have, it cannot filter water it isn’t getting.

A pool system works as a loop. Water has to get from the pool, through the skimmer and main drain, through the pump, into the filter and then back to the pool.

Interrupt that flow anywhere and the whole system starts acting strange.

That means before deciding your filter is bad, check the simple stuff:

• Is the pool water level high enough?

• Is the skimmer basket packed with leaves?

• Is the pump basket clogged?

• Is a valve partially closed?

• Is something restricting water before it ever reaches the filter?

Those are cheap problems.

Sometimes they’re free problems.

And that leads to one of my favorite pieces of pool advice:

Don’t buy the expensive problem until you’ve eliminated the free one.

Your Pressure Gauge Is Talking to You

That little pressure gauge sitting on top of the filter isn’t decoration.

One of the best things a pool owner can learn is their filter’s normal clean operating pressure.

Not somebody else’s pressure.

Not a number you found on the internet.

Your pool’s number.

Every system is different because plumbing length, pipe size, equipment, elevation and flow all affect pressure.

Once you know what your filter normally runs at when it is clean, the gauge becomes a useful diagnostic tool.

As the filter collects debris, resistance increases and pressure generally rises. A noticeable increase above your normal clean pressure is telling you it may be time to clean or backwash the filter according to the manufacturer’s recommendations.

And if that gauge has been sitting on zero since approximately the Reagan administration?

It may be time for a new gauge.

Sometimes the Filter Really Is Guilty

Once you’ve ruled out the simple circulation problems, then we start looking harder at the filter itself.

Depending on the type of filter, problems can include:

• A torn cartridge

• A cracked sand filter lateral

• A damaged standpipe

• A torn D.E. grid

• Internal parts that allow water or debris to bypass the filtering media

Those failures can let dirt travel right through the system and shoot back into the pool.

That’s when troubleshooting gets more interesting.

But there’s no reason to tear apart a filter—or start buying parts—before checking the easy stuff first.

Know What Kind of Filter You Own

One thing I keep coming back to with new pool owners is this:

You don’t need to become a pool technician.

You do need to know your own pool.

Know whether you have a sand, cartridge or D.E. filter.

Know where your pressure gauge is.

Know your normal clean pressure.

Know how your particular filter is cleaned.

And know what “normal” looks and sounds like when your pool is running correctly.

That little bit of knowledge makes troubleshooting a whole lot easier when something suddenly changes.

Watch the Pool Filter Video

I put the whole filter lesson together in the latest The Pool Gal Chronicles video, including how sand, cartridge and D.E. filters work, what your pressure gauge is telling you, routine maintenance and some of the problems that can make a perfectly innocent filter look guilty.

Watch the Pool Filter video here:
https://youtu.be/FRk31DwvF_c

And if you’re working your way through your own equipment pad trying to figure out what everything does, keep going.

We’re getting to know this pool one piece at a time.

Let’s get Pool Schooled.