The optimal centrifuge force is dependent on your sample. Generally we recommend you start with the most dilute form of the sample. For the 96 well filter plate format please use a low rcf ( <1000 xg ) in a first trial for 10 minutes. If the filtration is incomplete, increase the centrifugation time by estimation to drive to completion and /or increase the rcf incrementally to a satisfactory filtration rate. Do not spin at more than 2000 xg. Please use a good fitting collection plate below the filter plate. For micro-centrifuge format you can spin up to a max of 15k xg.