I just received my quick wicks in the mail and I bought them in 5/8s OD which works out fine because my MoodHoop is a 5/8 OD. But I was just curious because I'm not going to want to spin with my LED every time  and I wasn't sure what the equivalent in tubing size to a 5/8 OD PP to a tubing size of a PE. PE is just a tubing that is easier to access for me then PP or HDPE. I still have a ton of naked 1/2" PE hoops just sitting gathering dust but I know the tubing is too big to fit my 5/8s.  I just am not sure of the size lower...