I know I'm late posting to this thread; but I thought I would share anyway. Sounds like good advise given.
I normally cover mine for the 3 minutes. Then I blow off the out gassing after adding 1/2 cup water. I agree with you about the potency by covering.
I use lime juice to activate. I use the RealLime in the little plastic bottle. After 3 minutes, the color looks like my urine does after I have taken a B complex vitamin. ...a clear, bright slightly greenish yellow. Mostly yellow.