Relative Humidity and New Cyanotype

I have started playing around with Ware's New Cyanotype. I made up my own solution with chems from Artcraft. I found, after letting the brown bottle lie for a couple of days, there was about a tsp full of green crystals on the bottom which I discarded. I then filtered the rest back into the clean brown bottle. I have been getting an excessive amount of grain and brush stokes showing up in prints which had not been a problem with classic cyanotype. Can relative humidity in my environment (around 55-57%) be a culprit? Also, I apply sensitizer on arches platine taped on plexiglass and I dry it while taped. Could this be causing improper drying?