Your pump may be too large or the sand level too high in the filter. When the filter is backwashing the water flow can cause the sand to rise high enough and overflow into the standpipe, which will allow the sand back into the pool.
You shouldn't normally lose sand during backwashing. You should not have to add sand, ever. Only backwash when the filter pressure goes up 25%. There's no reason to backwash any more than this.
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.
Backwashing a filter too frequently will keep the sand so free of dirt buildup that it will not have the ability to remove the smaller particles of dirt and they will simply pass through sometimes causing cloudiness in water.
Turn the lever to RINSE, start the pump and rinse for about 15-30 seconds. Stop the pump and turn the lever to FILTER. This is the normal operating position. Close the drain outlet valve and start the pump.
Open the air bleeder assembly on your filter and turn pump on. Watch the pressure gauge for spikes. After the hose fills with water, backwash your sand filter for 2 - 3 minutes, or until water runs clear.
As a rule of thumb, regardless of if you have a sand filter or DE filter, you should backwash your pool about once a week during swimming season. The optimal time is right after you vacuum the pool. If your pool has had a lot more use than normal, it may be necessary to backwash twice a week.
Replacement sand for your sand filter typically costs around $25 per 50-pound bag, and your filter may require 100 to 600 pounds or more depending on the size and model. More than likely, you'll need about 350 pounds of sand for an average-sized inground pool filter.
The process of backwashing dislodges trapped debris and contaminants, flushing them out through your value's waste line or a hose that is connected to the pool pump. When the filter media is clean, the pressure gauge is lower and water can easily flow in and out of the system.
Although DE powder is used for filter grids, it can be added to sand filters. When the powder is added to the sand, the sharp edges of the DE powder enhance the filtering process of the sand by capturing tiny dirt particles during the filtering process.
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.
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.
It is not recommended to drain a swimming pool through the backwash valve. While sucking from the main drain and putting the water down the backwash line will work in some scenarios it puts your pool pump at risk of losing prime and running dry.
The dead algae is likely too fine to be vacuumed through your sand filter, therefore owners of sand filters must vacuum on the waste setting. Cartridge filter owners can vacuum up the dead algae but need to clean the filters thoroughly after doing so.
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.
Sand filters work by allowing water to cycle through a canister that contains sand. The water flows through the sand with ease, but larger particles are unable to pass through. Once the debris and other particles have been filtered out by the sand, a pump moves the clean water back into the pool.
Whenever the filter fills up with the dirt/debris it reduces the flow of water to your pool. Low flow = poor circulation which will lead to algae in the pool. Bottom line, the filter must be backwashed on a regular basis to ensure that your pool water is clear.
Overall, the lessons learned today is you should run your pool pump an average 8 hours a day to properly circulate and clean your water. The pump should push your entire pool in gallons in this 8 hour period of time. Residential pool water only needs to be turned over once daily to have proper filtration.
The size of your pool, the efficiency of your pump and filter, and how dirty your pool is are just some of the factors you need to consider. Nevertheless, most pool cleaning professionals would advise against running a pool pump for more than 8 hours a day.
It may be cheaper to run the pump at night, but honestly you should run it 1 hour a day per 10 degrees of temperature at least, and it should be during the day. Running the pump at night should only be when you are doing a major chemical treatment such as algae clean-up.