Skimmer not skimming(vertex in-100)

[apexifd]

it was skimming like a champ last week, but this weekend with the addition of bio pellet, skimmer hasn't has anything in the collection cup. I haven't been seeing those big nasty bubble on the top of riser neck.

Is there something I should look into?? eg, cleaning the pump??

thanks

Peter

[BlueTang<3]

Has the water level in the sump changed ? Can you adjust the skimmer a bit not familiar with this skimmer but might be something to check.