skimmer relentlessly overflowing

[landlubber]

good morning ladies and gents,
my system has been running for 2 years now and recently the skimmer has decided to freak out and hasn't found a way to resolve itself despite a complete cleaning of the skimmer, running activated carbon and 15% water change.
my next plan is to prepare fresh saltwater and basically do a water change using just the overflow skimmate in an effort to remove whatever contaminate is causing it grief.
any other ideas?

 

[Reefin Dude]

have you started doing anything differently lately? dosing something different?

G~

 

[Potatohead]

Make sure the air inlet is clear and not caked up with salt

 

[landlubber]

have you started doing anything differently lately? dosing something different?

G~

I just finished a flucannozole treatment about 10 days earlier and finished it by running activated carbon. both of those are not usual practices but the overflowing seemed to start 10 days following the time I removed the activated carbon.
the other new practice is using muriatic acid to lower the alkalinity of my freshly made saltwater but again it had no immediate effect as the problem started a couple of weeks later.

Make sure the air inlet is clear and not caked up with salt

yes the inlet is the very first thing I looked into. I generally find that if the inlet plugs the bubbles get far larger and instead of overflow my foam head refuses to rise.
great responses so far guys and I appreciate your input

 

[Reefin Dude]

any new cleaning products used in the house?

G~