Well, I've tried the new primeagra, and it has a unique tendency to build up a pretty thick salt crust on the top. The old primeagra didn't do this at all. I flush the pots every watering, and I'm still using tap water and 125 ppm N MSU.
Anyone have any experience with this? It's unsightly at best, and I don't want to be damaging the plants with it.