Welcome to the forums.
I have yet to get them, but many others recommend the Heartfelt industry beads for humidification. I beleive those work better than anything to keep the humidity level stable. Also they recommend keeping RH between 62%-65% that 70% is really too high.

Here is a link to the heartfelt page http://www.heartfeltindustries.com/Beads.htm
And again, WELCOME