I gave the collection cup a good scrubbing two days ago (taking care to keep my oily hands off the insides

After about 48 hours its still not skimming at all.
My
NO3 is climbing, I take that to be a sign that the skimmer should be skimming and isn't doing its job...
Back to PWCs. Any thoughts on the difference between a 10 % weekly
PWC vs. two 5 % PWCs a week?