Humidity in Racks too high.

Ok, I got all my tanks switched to racks. The room they are in stays between 75-85 degrees, but humidity here is only about 40ish%, so I used cypress mulch mixed with coconut husk in the tubs. I woke this morning to every tube being from 85% to 99% humidity!! I know it’s because the substrate is fresh and moist, but I can’t just let them sit in that high of humid. If I drill more holes, when the substrate dries out I’ll struggle to keep it up! So I’m at a loss...what can I do to maintain lower humidity?

I should mention I’m using an 8-tier AP Combo Rack

Something that might be worth trying before drilling more holes is to take out half (or more) of the bedding. spread it out on a metal baking sheet & bake on low heat until it's very dry. Then mix back into the rest of the bedding.