Book A Service Today!
Swimming Pool Sand Filters
These are probably the most widely and convenient filters used for domestic pools. They are operated by the various functions on the top of the filter called the Multiport Valve or MPV.
The common filter media used is fine silica sand although there are other mediums also used in the current market.
A Sand filter works by filtering the water through a bed of media, normally sand. As the media becomes more saturated with debris the smaller the particles it will remove from the water. Sand filters remove debris from 100 microns down to 20 microns from the water. Filter and pump flow rate need to be matched to ensure that the water is not forced through the media too quickly but also conversely enough flow rate is achieved to lift the bed of media to enable a sufficient backwash to take place.
One of the main benefits of a Sand filter is its simplicity of operation. Once enough debris is captured in the filter and the pressure on your gauge increases by 10 psi, your filter needs to be backwashed or cleaned. This can be typically required on a weekly, fortnightly or monthly basis depending on bather load, debris and water management.
The Filter Multi Port Valve Functions are:-
- FILTER - Set valve to FILTER for normal filtering. Also used for regular vacuuming.
- BACKWASH - for cleaning filter. When filter pressure gauge rises 8-10 PSI (0.55-0.69 BAR) above start-up (Clean pressure):
- Stop the pump, set valve to BACKWASH. Start pump and backwash until water in sight glass is clear.
- Approximately 2 minutes or less depending on dirt accumulation. Proceed to RINSE.
- RINSE - after backwashing, with pump off, set valve to RINSE. Start pump and operate for about 1/2 to 1 minute. This ensures that all dirty water from backwashing is rinsed out of the filter to waste, preventing possible return to the pool. Stop pump, set valve to FILTER, and start pump for normal filtering.
- WASTE - to bypass filter for draining or lowering water level and for vacuuming heavy debris directly to waste.
- RECIRCULATE - Water is recirculated through the pool system, bypassing the filter.
- CLOSED - Shuts off flow from pump to filter.
- VACUUMING - Vacuuming can be performed directly into the filter. When vacuuming heavy debris loads OR fine particles, set valve to WASTE position to bypass the filter and vacuum directly out to waste. The water level in the pool must be FULL to allow for vacuuming to WASTE.