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Whether you realise it or not the pool pressure gauge is one of the most valuable pool maintenance tools. This little guy is at worst ignored and oft times misunderstood.

Your eyes tell you your pool’s dirty, your chemical test tells you the health of your water but it’s the old faithful pressure gauge that tells you the inside story of your filter, pump and topside plumbing.

It’s a realtime monitor on the beating heart of your pool system.

You need to put on your pool doctors hat and understand what it’s telling you first. Then you’ll be able to come to a diagnosis. Your pool might need just a simple maintenance procedure or sometimes something a little more invasive.

So let’s take an a quick master class in pool pressure gauges so you understand how just how useful they can be to you.

Why You Need A Pool Filter Pressure Gauge

Water resists being pumped through our pool plumbing it has to be forced through, of course that’s what a pool pump does.

The water’s got to be pushed and pulled through valves and bends in the system, through the resistance of the filter, and then pushed uphill into the pool. It’s quite a challenge.

Our pool filter pressure gauge registers the pressure needed to push the water through the filter medium.

As far as we’re concerned a pool pressure gauge has just three basic readings, too high, too low or just right. Of course the first thing we need to know is what is “just right”, without that number we can’t work out the other two.

What Should My Pool Pressure Gauge Read

All pool setups are different and that means the sweet spot for the pressure gauge isn’t just a simple number. It depends on a number of variables. Plumbing size, pump size and filter medium are just a few of them.

It’s pretty easy to find the baseline pressure on your particular installation. If you’re confident the pump is working fine then just change out the filter medium and let the system run for an hour to let the filter bed in then take a pressure reading. You can consider this your baseline sweet spot.

Not everyone wants to renew the sand in the filter of course so the next best thing rather than a simple backwash is to add some filter cleaning fluid.

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HTH 67015 Filter Cleaner Solution
  • BENEFITS: Helps the filtration system work more efficiently; Cleans cartridge, sand or D.E. filters

This should give your sand a deep clean and remove dirt, lotions, creams, body oils and other pool contaminants, Then go ahead and take your benchmark reading.

Pool Pressure Gauge Is Reading High

Of course there’s a number of things that can cause a high pressure reading. We’re going to take a look at the most common first.


The first and most obvious is a dirty filter or dirty filter medium. It’s quite rightly the first thing a pool owner thinks of, and of course the easiest to fix.

Either backwash the sand or pull the filter and replace with a new cartridge or soak it in a good filter cleaner overnight.


Pump output must not exceed the maximum specification of the filter. If it does at best the finer will be inefficient and at worst it could be dangerous. A pump flowing at a higher rate than the filter can handle  will obviously increase the pressure.

If you’ve installed the correct replacement pump it will usually affect your bench mark pressure so you simply need to re-calibrate your baseline reading to the new pressure.


Excessive sand in the filter is not too common a cause of high pressure readings but if you’ve just changed it then it’s something to consider.

More common is using a different make of cartridge filter. Two filters may look the same and both fit but internally they can be significantly different leading to an instant increase or decrease in pressure.


Generally pool valves will serve for much of the lifetime of the pool, typically 10 to twenty years. They don’t break and there’s not much to go wrong with them. However a faulty or partially blocked valve on the discharge side of the pump will cause anomalous pressure readings. It’s pretty rare but can happen.


A build up of air inside the filter caused by an air leak before the pump on the suction side of the plumbing will cause back pressure. Open the bleed off valve to release any trapped air air in the system. The pressure should return to normal. If the problem reoccurs it’s time to start to seriously investigate an air leak.


Becoming quite a popular retro fit addition to pool plumbing these days. They’re a great idea but be prepared for a significant increase in system pressure when they’re fitted.

Pool Pressure Gauge Is Reading Low

This is a little easier to diagnose because there’s less causes so less things to trouble shot.


Quite common and an easy, cheap fix.

Cheaper pool pressure gauges can be subject to warping especially if sighted in the full sun for a period during the day. Just tapping on it might spring it back into life, if that’s the case then it’s time to change it out for a new model. They’re surprisingly inexpensive so you can afford to invest in a good one. .

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  • For pressure measuring on the filter of swimming pool,Spa, Aquarium Water etc

There is a wide variety of after market gauges available with back or bottom threaded options. We prefer the ones with a convenient bezel so you can set and view your base line pressure.

If you’ve tapped the gauge and it doesn’t respond the next step is to take it off and check it hasn’t become clogged with debris. Also run a fine screwdriver or wire down through the female thread to check for blockages there too.


If everything checks out it’s time to inspect the lines running back to the skimmer. Visually check if the water flow from the pool seems normal. If it seems a little low the skimmer itself could be blocked or the pump basket.

That just leaves the pump or the lines to the pump itself as the suspects. First visually check the pool jets if there’s bubbles coming out it indicates air in the system ( the exception is the newer model Intex pools that actually have jets that are built to add air bubbles into the pool ) If there’s bubbles check all the plumbing joints before the pump.

The easiest way to do this is to use a bubble bath foam and offer it up to the joints and pump and if it’s sucked in then you’ve found your leak. That’s the system we use, it’s very effective and smells nice too!!

Lastly it can be a clogged pump impeller which is more challenging. Unfortunately the pump’s got to be removed and dismantled to identify this problem. It’s the last resort if all else fails.

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