It is important to use a Tommee Tippee Perfect Prep Filter with your Perfect Prep machine. Most standard water filters don't include an anti-bacterial filtration membrane so will not remove bacteria. It is therefore extremely important to ensure that you are buying and using the correct Tommee Tippee anti-bacterial filter. Please see below how the Tommee Tippee Filter works. 1) The micromesh removes larger particles such as sediment and fibres 2) The water moves into the section containing ion e