The filter must be sized to match the pump. Filter flow rate is the velocity that water moves through the filter and depend on filter area. The slower the flow rate, the better the quality of filtration. If the filter is undersized (area too low=flow rate too high) filtration quality is poor and it becomes clogged very soon. But if the filter is oversized (area too high=flow rate too low) the pump flow available is not sufficient for a good filter back-washing.
The general rule of thumb for filter rate margin is:
* Sand filter: 37-50 m³/hr/m² (15-20 GPM/FT2).
* Zeolite filter: 30-40 m³/hr/m² (15-20 GPM/FT2)
* Diatomite filter (DE): maximum 5 m³/hr/m².
* Cartridge filter: maximum 2.5 m³/hr/m².
Once we select the flow rate, the filter diameter is calculated and displayed for sand and zeolite filter. For cartridge and DE, the filter area is calculated and shown since that is the applicable criteria of selection for these types of filters.
1a. First select the right pump in panel 'Pump selection'. The pump flow is then used as input for the filter calculations.
2a. Then go below to the panel FILTER SIZING, sand and zeolite type.
3a. The CALCULATOR assumes by default a sand filter based on a filter flow rate of 40 m³/hr/m² and shows its size in the field 'Filter diameter'. If you prefer a bigger or smaller sand filter, or your filter is a zeolite filter, go to next step 4a.
4a. Enter in the field 'Filter flow rate' the desired value and press the Enter key, or move the Filter flow rate slider selector to the desired value within the slider scale. Please, check that selected 'Filter flow rate' is within the proper range depending on filter type, sand or zeolite type. The filter size is then shown in the field 'Filter Diameter'.
5a. You can also directly enter the desired filter diameter in the field 'Diameter filter', press the Enter key and you read in the field 'Filter flow rate' the flow rate to the new filter size entered. Be careful that the filter flow rate is within the right range for your sand or zeolite filter type
1b. First select the right pump in panel 'Pump selection'. The pump flow is then used as an input for the filter calculations.
2b. Then go below to the panel FILTER SIZING, diatomite and cartridge type.
3b. The CALCULATOR assumes by default a Diatomite filter based on a filter flow rate of 4 m³/hr/m² and shows its size in the field 'Filter area', 0,62 m². If you prefer a bigger or smaller DE filter, or your filter is cartridge type, go to next step 4b.
4b. Enter in the field 'Filter flow rate' the desired value and press the Enter key, or move the Filter flow rate slider selector to the desired value within the slider scale. Please, check that selected 'Filter flow rate' is within the proper range depending on filter type, DE or cartridge type. The filter size is then shown in the field 'Filter area'.
5b. You can also directly enter the desired filter area in the field 'Filter area', press the Enter key and you read in field 'Filter flow rate' the flow rate for the new filter area entered. Be careful that the filter flow rate is within the right range for your DE or cartridge type