Was the Huber needle you were using the right length? I've seen various lengths ranging from 1/2 inch to 2 inches. When you inserted the Huber, did you 'feel' the needle hit the base of the port?
I'm curious about the order to change the Huber every 3 days, I've worked oncology at a couple facilities and policy has always been to change the Huber every 7 days or as needed...though I am only familiar with mediports, perhaps they're different than porta caths?
I'll take accessing a mediport over getting a peripheral IV any day, my IV skills aren't the best after dealing with mediports for my first few years as a nurse...no longer in oncology now, co-workers on my current floor are a bit intimidated by the occasional mediport we'll get, so we trade: I'll access their port, they get my peripheral, lol