The pump used for backwashing filters shall have sufficient capacity to provide a rate of at least 15 gallons per minute per square foot (10 L/s/m2) of filter area.
Another industry standard is to backwash when your filter's pressure gauge reads 8-10 PSI (pounds per square inch) over the starting level or “clean” pressure. For example, if your filter is running normally at 15 PSI but increases to 25 PST, you should perform a backwash.
Additionally, the World Health Organization (WHO) recommends a backwash flow rate of 15-17 gpm/sf. Per Steve Andrews, the President of Nemato Corporation, a backwash rate should be determined by the filter bed expansion fluidization.
If the manufacturer of the mineral you are using recommends backwash rate of 10 to 12 gpm per square foot, use the low range on cold water and the high range on warmer water.
If backwash rates are too high, significantly more media could be lost— compromising filter performance. In any case, it is important to measure, track, and replace any missing media during your annual filter inspection and maintenance check.
The pump used for backwashing filters shall have sufficient capacity to provide a rate of at least 15 gallons per minute per square foot (10 L/s/m2 ... /s/m2) of filter area. The filter backwashing facilities shall be sufficient to backwash at the rate of 15 gallons per minute per square foot (10 L/s ...
Generally speaking, a pressure reading between 10 – 25 psi can be considered normal.
SCHEDULE A HIGHER-SPEED PUMPING TIME
This is an appropriate speed for backwashing and will clear out any air bubbles that can form in the pump and plumbing during the lower RPM period. For an average pool, set the speed to around 2,100 and 2,600 RPM.
At ambient temperature, the recommended filter backwash rate is 6-8 gpm/ft² for anthracite and 13-15 gpm/ft² for sand. Anthracite filters associated with hot process softeners require a backwash rate of 12-15 gpm/ft² because the water is less dense at elevated operating temperatures.
Filter & Backwash Velocities:
For DAISY a filtration velocity in a domestic pool of between 20-30m/h and for commercial 15- 25m/h. A backwash velocity of min 45m/h is required for both domestic & commercial. This may vary depending on the temperature and salinity of the water.
What is the Filter Backwash Recycling Rule? The FBRR requires filtered surface water suppliers using conventional or direct filtration to, where needed, change the return of recycle flows in their plant's treatment process.
Backwashing too often can reduce the filter's effectiveness. The sediment layer helps improve filtration by trapping finer particles. If you backwash before it's needed, you lose this beneficial layer, which can result in cloudy water.
Constructive waves
are: strong swash and weak backwash. the strong swash brings sediments to build up the beach. the backwash is not strong enough to remove the sediment. the waves are low and further apart.
Filtration and backwash rates are calculated by dividing the flow rate through the filter by the surface area of the filter bed. Typically these rates are measured in gallons per minute per square foot of filter bed area.
Turn on the pump and allow the sand filter to backwash for 2-3 minutes or until the water in the sight glass (typically located on the top of the filter) is visibly clear. How long you backwash the sand filter for is not critical though you should visibly see clear water within 2-3 minutes.
Backwash water is discharged into the main distribution inlet header for reprocessing. Air from the blower is used in a semicontinuous pulsed-bed filter. When the suspended solids in the effluent cease to filter to an acceptable level of the head, pressure begins to increase, and backwashing begins.
According to most design manuals, the min- imum backwash rate on a rapid-rate gravity filter should be eight to 15 gallons per min- ute per square foot of filter area, depending upon whether the filter is equipped with an air scour system (eight gallons per minute per square foot if it is equipped with an air scour ...
Proper backwash flow rate is 6 gpm per square foot of resin bed surface area. If the backwash flow rate is significantly greater or less than 6 gpm per square foot, contact a softener service technician to adjust the backwash to the correct flow rate. Backwash should continue for 10-15 minutes.
Typically, 8 hours of run time is sufficient but the longer, the better. Running the pump during the hottest parts of the day helps to combat the effects of the sun, especially with deterring algae growth and removing bacteria and debris during peak swim times.
While it's not strictly necessary to backwash before vacuuming, doing so can significantly enhance the efficiency of your vacuuming efforts.
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. If you've cleaned the filter recently and you're still showing an above-normal PSI, check for leaks in your filter system.
If the pressure gauge continues to read high after you've cleaned the filter, something isn't working right. Something is preventing water from flowing back into the pool after it passes through the pump. Check for any of these problems: The returns or return valves are closed, partially closed, or blocked.
What's The Correct Filter Pressure Gauge Read? Most filter systems are designed to operate in the 5-15 psi or 10-20 psi range. The way to find out your particular correct pool filter pressure is to clean or backwash the filter thoroughly and empty the pump and skimmer baskets.