I have Pari Green and Pro Neb from Pari. Used with sprint cups. I have found that how you clean them is the key. Soaking in vinegar will dissolve any build up from hard water. I also notice that since we had new tanks for our whole home water purification system installed that the cups are working even better. One of the tanks is a descaler for hard water (which we have). So now when I boil the cups for 5 minutes it is not an issue (the hard water). But could be your compressor is needing a swap. They will send you a new one for free if you call them. Or if the filter needs changing that can make a BIG difference. Both my systems only take under 10 minutes on average. To me they go too fast and I often use a second vile of saline since I need to nebulize for some time to get benefits!