We handed over another composite liner pool in Oxford in North Canterbury last week. It must have been the wettest day on record with a State of Emergency declared shortly afterwards. Driving to this property we were in passing through water that was sometimes halfway up our wheels!
We were committed to the handover as our client was so excited to get their new pool. So there we were in full wet weather gear running through Pumpshed 101. Of course we addressed many questions but the one I want to answer today is… how often should we backwash our filter?.
Why do we have a filter on our pool?
Filters are installed on pools to remove debris that enters the water and ensure you have the cleanest possible water to swim in.
How many filters are there in my pool?
Your pool filtration system will typically have three filters. The first filter is a basket in the bottom of the skimmer ie the white box on the side of the pool with the round lid beside the pool. The purpose of this filter basket is to remove large items like balls, toys, leaves or anything else that could block the pipework in the ground.
The second filter is in your pump ie the machine that sucks the water from your pool and then pushes it through your filter ie the big round bulb in your pump shed. This filter like the skimmer filter is there to prevent larger debris from entering the pump and blocking it.
The third and final filter is the filter media inside the filter shaped like a large bulb. This filter was traditionally filled with fine sand. Now days we use glass and at MORGAN+STONE we use a superior spherical glass product that removes fine particles down to 3 microns in size.
What are the benefits of quality filtration?
The higher the quality of your filtration media ie how small a piece of debris it will remove, the fewer particles in the water the greater your water clarity. The clearer your water the more attractive and inviting your pool will look.
How do I clean my filter?
Cleaning your filter is achieved by backwashing your filter. In simple terms… switch off your pump, move the handle on the dial on top of your filter to backwash and restart your pump. Water will then be forced backwards through your filter ending up in the sewerage pipes leading away from your property.
On every filter there should be a small clear bit of plastic called a sight glass allowing you to see the colour of the water. We recommend letting the pump continue until you can see clearly through the water passing through this sight glass.
Once the water is clear you can turn off the pump, turn the handle to rinse and then restart the pump for a short time of 10-20 seconds. The purpose of rinsing is to wash the top layer of your filter media after it has settled post backwash.
How often do I need to backwash my filter?
If your pool water is well maintained and you live in an area that doesn’t have windblown debris and dust then it is likely you will not need to backwash more than once per month. On the other hand if you have lots of organic matter, dust and debris entering your pool then it makes sense you will need to backwash more frequently.
How do I know when I need to backwash?
You will notice on your filter there is a pressure gauge. The main purpose of this gauge is to tell you when the pump is working harder to push water through your filter. When your filter is dirty it is harder for the pump to push water through the filter. This in turn will increase the resistance and therefore pressure gauge will show increased pressure inside the filter.
There are no exact pressure numbers we can give you here for your filter as each pool filtrations system registers a slightly different pressure when clean. So… the easiest way to monitor your pressure gauge is to mark where the pressure sits with a clean filter. Then when you notice an increased pressure reading you will know to backwash your filter. Over time you will learn the intricacies of your own filter.