Your filter may be clean and normal at 9-10 psi, but your neighbor's filter gauge could run higher, and be clean at 15-16 psi. Some systems with very low resistance can run very low pressures, barely registering, while other filter systems can run quite high, pushing 30 psi when the filter becomes dirty.
In most high-rate sand filters, it's time to backwash when the pressure differential reaches 18 to 20 psi. But if the system has only an inlet pressure gauge, you should backwash when the pressure increases by 8- to 10 psi from initial post-backwash readings.
Generally, if your pool filter water pressure rises more than 10 PSI over the normal range, it's time to clean – or possibly even replace -- your filter. For most filters, 20 or 30 PSI is considered too high, but you should consult your pool professional to make sure that's true for your model.
Normal pressure for most pools is between 10 and 25 PSI (70-170 kPa). The pressure for filtration systems varies depending on the type of filter, the size of the lines, the pump and other pool equipment.
The pressure gauge should read approximately 50 - 70 kpa when the filter is clean. Backwashing is indicated when the pressure exceeds 70 kpa.
High swimming pool filter pressure is usually the result of a lot of particles being filtered out of the swimming pool water. When pressure rises it is time to backwash the filter if you have that option with a sand or diatomacesous earth (DE) filter.
On average, a pool filter cartridge's pressure reading, in PSI on the filter gauge, should read between 8 – 15 PSI. If you are experiencing an 8-10 PSI increase in pressure, somewhere up around 25-30 PSI or higher, this means that it is time for you to clean your filter!
The most common reasons why a cartridge, sand, or DE filter's pressure rises quickly, even after cleaning or backwashing, is a clogged or blocked filter, algae or old filter elements. If any of these things are wrong, the pressure can rise rapidly in minutes, hours or days.
How Often Should You Backwash a Pool Sand Filter? As a general rule of thumb, you should backwash and rinse your filter about once a fortnight. The optimal time is right after you vacuum the pool. However, if your pool has had a lot more use than normal, it may be necessary to backwash once a week.
Add diatomaceous earth (DE) to your pool skimmer, stick to around a scoop or two – no more than the size of a 1lb coffee cup. The moment you do this, go to the pool jets to see if it is returning DE into the pool, or if the water suddenly looks cloudy. If it is, you likely have an issue with your filter.
It could be a clogged pump basket, impeller, pipe, or skimmer basket. It could also be a closed or broken valve before the pump. In some cases, the pump may have an air leak and is drawing in more air than water. This can reduce filter pressure (and filtration ability).
Check the Valve
The first thing to do to increase the suction is to check for blockage and air leaks. If one of the skimmers does not suck, it would be necessary to remove the basket from the skimmer. Then check if there isn't a flow control valve at the bottom of the skimmer, which would be almost closed.
Can You Backwash Too Much? If you backwash your pool too much i.e. time duration and/or close frequency then yes you can cause a lot of problems. Some problems that can arise from backwashing your sand pool filter too much are: Loss of water – 500+ litres of water can be lost in each backwashing cycle.
The most common reason for weak jets is an air leak. An air leak would come from the suction side of the system. This would be the area between the skimmer and the pump. One way to determine if you have an air leak is by looking for air bubbles coming out of the return jets.
Filter. The lever should be on the 'Filter' setting most of the time. This is the setting that provides normal pool filtration by pushing the water through the filter media (sand, glass beads or D.E) that then traps any dirt and debris before the water is returned to the pool.
Too much sand and your filter will likely not run correctly or may break when reassembling. Too little sand and you will have cloudy water no matter how much your filter runs.
When do I need to replace my sand? On average, sand should be replaced every 3-5 years. This may be longer if the pool stays clear, or shorter, if the filter runs all the time. The jagged edges of the sand wear down and become smooth as the sand ages.
The rule of thumb is generally 8 hours, although it could be anywhere from 6-12 hours, depending on your pool's size. Each pool is unique, so to keep your pool pump efficient and effective, you need to figure out exactly what your pool's turnover rate is.
Rinse the filter for about 1 to 2 minutes or until the water in the sight glass is clear. NOTE: Any electric heater must be off. Stop the pump. Turn the lever to RINSE, start the pump and rinse for about 15-30 seconds.
Wait for a few minutes until the water runs clear. Turn off the pump to cease the backwashing. Turn the filter valve handle to RINSE and ensure the handle locks in place. Allow the rinse process to occur for 1 minute or until the water is clear.
Adding too much DE to your pool may cause multiple negative results. These ramifications include a clogged skimmer, turning the pool cloudy, reducing the circulatory pressure in the pool and putting too much work on your pump that may result in eventually breaking the pump.