The pressure gauge on your salt water pool filter helps to indicate when there is a problem with water pressure before the filter (low pressure) or within the filter itself (high pressure). Each pool’s filter pressure gauge can act differently so there isn’t necessarily a set number to look for that indicates you have a problem. Many pool pressure gauges are capable of showing a reading of between 0 and 60 psi like the photo above but actually operate normally between 5 and 20 psi.
In general, if your pressure gauge goes 5 – 10 psi (pounds per square inch) higher than normal, it indicates that the filter needs cleaning or backwashing and that the issue is within the filter itself. If pressure drops below its normal reading, this indicates that the problem is before the filter possibly leading into the pump and could indicate a blockage somewhere in the system.
Some pool filter pressure gauges actually come with a marking that indicates the acceptable low and high pressure ranges that effectively tell you when the filter needs to be washed or backwashed. In other cases, you might want to put a pen mark on your filter’s normal pressure reading when the filter is clean to monitor when it starts to rise and indicate it needs to be cleaned.
Pressure Gauge Is Too High
When the pressure gauge runs between 5 and 10 psi higher than normal, it’s most likely an indication that your filter needs to be rinsed (cartridge filter or D.E. filter) or backwashed (sand filter). The most common reasons your filter pressure gauge is running high are from the following:
- Dirty filter mediums (cartridges that need to be rinsed or sand filter needs to be backwashed).
- Filter mediums that need to be replaced (cartridge filters that need to be replaced or sand filter needs new sand.
- Blocked water return jets inside the pool.
- Broken parts inside the filter.
- Malfunctioning pressure gauge that isn’t reading correctly.
Pressure Gauge Is Too Low
- Skimmer basket or pump basket that is full or otherwise clogged and needs cleaning.
- Blocked main drain or skimmer or damaged pipes that are cracked and leaking.
- Valves (main drain, skimmer) were accidentally closed or partially shut off.
- Loose pressure gauge or another opening somewhere in the system that is allowing air in.
- Malfunctioning pressure gauge that isn’t reading correctly.
Some of the above-mentioned issues you can tackle yourself because they have to do with regular maintenance (cleaning, rinsing, backwashing) but other more serious issues may require your pool company taking a look to fix them.
If you find that pressure jumps up and down each day or is constantly sitting at 0, it’s likely that there is a problem with the pressure gauge itself. Assuming that tapping on it lightly to move it doesn’t help, it may be time for a new gauge.
Pool Vacuuming
A pool vacuum typically works by utilizing the opening of the skimmer to provide suction to the vacuum head. So you take the skimmer lid off, remove the skimmer basket and attach your pool hose to the skimmer opening to provide suction for the pool vacuum. If you have a separately functioning high end robotic vacuum with its own motor, it may operate independently of the skimmer and thus not require it.
But when you utilize the skimmer suction for vacuuming, a malfunctioning system where water pressure is too low can negatively impact vacuuming. The stronger the suction from the skimmer, the better and easier vacuuming will be. Having tried using our lower end auto vacuum, I have experienced poor vacuuming when the water pressure was low and had to address the issue before vacuuming the pool.
On the other end, if water pressure is too high, it can also cause the problem of the pool vacuum almost being stuck to the floor of the pool because the pressure is so strong. Similar to how if you vacuum a small floor rug and it gets sucked up into the vacuum and won’t let go. This is an easier fix as you can slightly close off the skimmer valve or open up the main drain valve slightly to reduce pressure.
Final thoughts
The PSI (pounds per square inch) on a pool filter can vary depending on the type of filter and the specific manufacturer’s recommendations.
In general, a clean cartridge pool filter should have a PSI reading between 8 and 12 PSI. However, if your filter is new or has recently been cleaned, the PSI reading may be lower. As debris accumulates in the filter, the PSI reading will increase, indicating that it’s time to clean or backwash the filter.
As a general rule, a clean sand filter will typically have a PSI reading between 8 and 10 PSI higher than the start-up pressure. The start-up pressure is typically indicated on a label on the filter or in the manufacturer’s instructions.
It’s important to consult the manufacturer’s instructions for your specific pool filter to determine the recommended PSI range. You may also want to consult a pool professional to ensure that your filter is operating at optimal efficiency.
A quick check to see how your water flow is: Put your hand in the water near the water return with the pump running and feel the force of the water coming out. A lower level of water return often indicates that the filter needs cleaning, whether rinsing cartridges or backwashing.
Conclusion
- Pool filters operate at different pressures but in general pool pressure gauges are capable of show a reading between 0 and 60 psi.
- Most pool filter gauges will show a normal range of 5 – 20 psi when operating correctly. When the reading goes 5 – 10 psi higher than the normal range, it usually indicates a filter cleaning or backwashing is necessary.
- If the filter cleanliness isn’t the problem, there could be other issues for a high pressure reading such as a blockage somewhere in the piping or system in general.
- A low pressure reading might mean a full skimmer basket or pump basket or a bad leak somewhere in the system among other reasons.
- You may also have a problem with the pressure gauge itself and it might simply need to be replaced.
- Learn more about the three main types of pool filters to understand the differences and pros and cons of each.