Upcurled leaves is a sign of too HIGH humidity???

My room is always been on the low side, and I'm battling to keep it more moist. It's always 20%- 35%...Trying to keep it in the high 30's...

As for water, the ph out of the bottle is 6.1-6.2, I realize that is a little low, and I have measured after the calmag (6.5) (so yes I was phing it with the calmag). The only phUp I have is the one for aquarirums (which is a no-no) and I haven't used that. Any natural alternates to phUP the water?