i have a 1588 hovabator (which i love) and i filled an extra trough this time around and my humidity was at 72%. so instead of trying to suck some water out, i just put a small object (very small) in the lid to pop the lid just a crack and now the humidity has been around 67%. you could maybe try that.
I have a hatch due today. I hear one peeping, but no pips yet. Only 6 made it to lockdown. I need these guys to hatch quick so I can put more in. I have pheasant eggs to lock down and I've never hatched them out before. Afraid the chicks will play pinball if I put those tiny eggs in there with them. LOL