I am having a very similar problem. After a couple of weeks of trying 50/50 distilled water-Glycol solution, I am only up to 64%, though I did manage to get the temp. pretty much perfect (about 70-72 degrees).

I might try the Heartfelt beads. What's the difference between the 60, 65, and 70 Ph Beads, is this the level of humidity that the tube is designed to maintain?