Protein Skimmer Issues

Hello,

I am having an issue with my protein skimmer. I have read a ton of forums and post regarding this issue but nothing seems to work. I run my skimmer and everything works great for a few hours. The foam builds up but once it starts to overflow into the cup, it suddenly drops to no foam at all. It used to run great and is a little over a year old. It has been cleaned and well maintained.

I have tried to adjust the water level to bottom of the cone, mid way and at the top. I do have nitrates in the water and a reactor so there should be sufficient material to remove.

Any suggestions on why this would be happening?

Coralife Protein Skimmer 125 Gallon

Thanks for the help!