Blue tape is the only thing I have tried, and it was brand new tape, so that shouldn't be the issue. I used the recommended temp for  nylon 230 but first layer I did ten degrees celsius hotter. It needs to be hot for a long time before the nylon comes out. When I preheated the head several times it worked best. After the first few layers were down it worked great. Getting them to stick was messy and it globbed the head several times when I didn't watch it close. Have you done much with nylon?