New to Screen Printing

Hello everyone,

I am fairly new to the screen printing world. I currently work with Everything Signs in Minnesota. We added screen printing to our business about a year ago. We went to Chicago to get some training as we knew there were many parts to figure out! We currently use almost all products from Ryonet. However, we've been having a few problems mainly with the ink. We've noticed on some of our shirts that usually the white ink wears away too quickly. It doesn't come off after one wash, but it breaks down after a couple more washes. Is there recommendations over which brand is better? Or it could possibly by curing time, but it doesn't happen to any other colors. Any input would be amazing!

Thanks,
Ashia Volkers