HOB Skimmer Help Needed

[RuGlu6]

If impleler has no damage you do not need to replace it. The air line that goes to the ventury might be plugged with salt deposits happens all the time to ventury skimmers.
Get that air line line soaked in vinegar or water (vinegar is best it will dissolve all the calcified deposits in 24 hrs) and clean that air line by blowing in to it.
All it is is some debris stuck in there that you need to get rid of.

Or there is a crack in that air line under water serfice and it sucks water instead of the air. In that case replace the air intake line. (larger diameter air intake line is better it will allow more air in and will get plugged slower)

HTH.