Ima try to chance the carbon, and also clean the airline tubing in the skimmer.
I tried adjusting the level by raising it another inch and a half, but no luck with the foam stoping

is the water output at full open? that should lower the level in the skimmer internally. You may need to raise it higher BUT if this is just a temp thing you may not want to mess with it too much or it will skim like crap once the meds leave the system.

May want to just turn it off and just do water changes daily - though that might dilute the medication. I have never treated for ich so i dont know if the instructions advise AGAINST water changes...

I think it may be a medication thing, because the first day I dosed, I turned it off, then after about 2 or 3 days of dosing I thought I would turn it back on, and stuff just started going crazy