For an average pool, set the speed between 1,500 RPM and 2,000 RPM. You'll want to run your pump at a higher RPM for approximately two to four hours every day. 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.
There is not an exact speed to use when backwashing the pool filter. Normally, it's something where you want to use one of the higher speeds to ensure plenty of water flow when doing this. I would say 2800 rpm is a good place to start and then you can adjust up or down as needed.
As a general rule, you should be backwashing your pool about once a week or in conjugation with your scheduled maintenance. 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.
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.
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 ...
Backashing relies exclusively on return water whose velocity has to be adjusted to the material's granulometry and to the water's viscosity and, therefore, its temperature. In general, velocity is between 15 and 50 m/h or even more at high temperature.
Avoid Backwashing Too Frequently:
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.
In order to prevent residual blow back into the pool, once you've finished backwashing it's highly advisable to rinse the filter. Just as the backwash lifts and flushes the sand, the rinse resets the sand to its original position for optimum filtration.
Backwash run times can be anywhere from 5–20 minutes with rates ranging from 8 to 25 gallons per minute per square foot of filter bed area, depending on the quality of the pre-filtered water. Filtration and backwash rates are calculated by dividing the flow rate through the filter by the surface area of the filter bed.
While it's not strictly necessary to backwash before vacuuming, doing so can significantly enhance the efficiency of your vacuuming efforts.
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.
Backwash – In this position, the water direction is reversed which allows the debris and dirt collected during the filter stage mentioned above to be flushed out to waste. This also helps maintain a proper filter pressure. Now we'll move on to the less frequently used and understood options.
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.
For an average pool, set the speed to around 2,100 and 2,600 RPM.
Dual Speed Pumps: AKA Two Speed
Dual-speed pumps also cost a bit more than single-speed pumps as far as upfront cost is concerned. But if you operate it properly you can have significant energy savings.
Efficient backwashing removes captured particles from the filter without losing the anthracite or sand media. In actual practice, it is normal to lose up to an inch of media per year during backwashing. If backwash rates are too high, significantly more media could be lost— compromising filter performance.
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.
Backwashing can take only a few minutes to complete, but for a typical pool, it consumes approximately 200 to 300 gallons of pool water! So, while your filter is losing unwanted dirt and debris—your pool is losing a ton of water.
If you're dealing with an algae infestation, brush the pool after shocking to remove lingering debris and run the filter. Rinse or backwash your filter to avoid recontamination. If you've still got traces of algae, shock your pool again. After shocking, test your water chemistry.
Fast Rinse Backwash is followed by the fast rinse cycle.
Use a vacuum or backwash the pool to remove the dead algae. Apply a mustard algaecide following the label directions. Allow the water to circulate for 24 hours. Use a pool vacuum or backwash the pool again to remove the remaining dead algae.
Multi-port backwash valves
have a tendency to leak water into the backwash line when the seat gasket gets worn out or the handle was not fully pressed while turning the valve to set to the backwash position.
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.