You will get it!!! What medium are you using? If soil/soiless mediums are your mainstay, there is a tool called an Accurate 8 soil ph probe(48 bucks). it tells you exactly your soils ph right out of the bag!!! PH is what sounds like your problem is. Most mediums are roughly a ph of 7 out of the bag, so if you are giving 6.5, you are too high to begin with, and the soils ph goes up as the pot dries out. Try dropping down to 6.2 and see what happens. BUT before you do, get a good read on your ph of your runoff. That will tell you what you need to do.
