Pour a glass and watch it for a minute. Cloudiness that clears from the bottom upward strongly suggests tiny air bubbles. Dark specks or cloudiness that persists should be investigated separately.
Trapped air is common after opening the system
Changing cartridges introduces air into housings, tubing and the membrane assembly. When that air breaks into tiny bubbles, the water can look white or milky until the bubbles rise out.
This often improves after the system is fully flushed and normal pressure stabilizes.
New carbon filters can release fines
Loose carbon dust from a fresh cartridge can appear as gray or black particles during startup. Proper flushing is important before drinking the water.
Persistent particles after the required flush can point to an incorrectly seated, damaged or unsuitable cartridge.
Check cartridge seating and flow direction
If cloudiness began only after service and does not resolve, recheck that every cartridge is the correct model, installed in the correct direction where applicable, and fully seated with intact seals.
Leaks, bypass around a seal or an improperly installed membrane can create other performance changes at the same time.
When cloudiness deserves more attention
Cloudiness that does not clear in a glass, unusual odor, persistent visible debris or a sudden change in source-water quality should not be dismissed as trapped air. Stop and identify the cause before continuing normal use.