I am wondering where problem could be. I am not working directly with this probe what you asking about, but the first and the most important is concentration of prepared staining solution or fixatives as well. Moreover time and conditions of incubation is very important.
Actually I am aware about the points you mentioned.
What I am just asking is this dye I am is using (I already have one, dont wanna buy another) is smaller crystal and in tar form. More proper to use as solution form not crystal.