TL;DR: how would negative pressure and blowing out the air from the tent change my setup?

Right now, I use an old PC fan inside the tent, which continuously blows fresh air from the outside through a slit. It’s constantly on, but pretty weak.

The FAE isn’t optimal for my oysters, but sufficient. The stems are slightly prolonged, but still totally fine.

Right next to the fan is the tube of my terrarium fogger, and the fan disperses the fog inside the tent. The RH is always about 75-90%, which is fine for me. And the underside of it is opened, so the CO2 flows to the bottom and gets out of it.

The setup itself works fine, but I have one major problem: water consumption.

The room, where the tent is located, feels really humid, which isn’t great in regards of molds, especially in the winter.

I need to use a lot of (destilled) water, which is also expensive. For my roundabout 2x1,50 m tent I consume about 5 liters a week, which is a lot!

Sometimes, it condensates on the outside and pools up at the bottom tray.

I thought about creating a suction tube at the bottom, which draws out the “used” air and blows it outside the window. So, basically, negative pressure instead of slight positive. I already have a fan for that lying around. It is a lot stronger, do I need to choke it a bit? What cycles of “on and off” would you recommend?

Is programming an arduino a good idea for that? What alternatives would you recommend instead?

How would that, all in all, change the things, especially the water consumption?