DIAGNOSIS The pink film is Serratia marcescens, a common airborne bacteria that thrives in moist environments. It is not coming from the filter but growing in the stagnant water of the lower chamber.
FIX Step 1: Empty and disassemble the entire system. Step 2: Clean the lower chamber, upper chamber, and lid with a solution of 1 tablespoon unscented bleach per gallon of water. Step 3: Scrub thoroughly, especially under the spigot interior. Step 4: Rinse all parts completely with filtered water. Step 5: Allow to air dry completely before reassembly.
IF THAT DIDN'T WORK Increase cleaning frequency. The lower chamber should be cleaned with a mild bleach solution or vinegar weekly if used in warm, humid conditions.
HEADS UP Do not use scented bleach or harsh detergents. They can leave residues that affect water taste and are difficult to rinse fully. Regular drying breaks the bacterial growth cycle.