Tub/Humidity question

I thought that this might need to go in the caging forum, so sorry if its meant to be there and not here.

My question is, how fast should I be losing humidity in my tubs? How much ventilation do I need?

I've just finished my 4 tub rack, and I've been testing my heat and humidity. Heat is fine, with high 80's ambient, and low-mid 90's on the hot side. So thats all good as far as I can tell, but I tested my humidty by spraying the tub down and getting a base and seeing how it holds. Well, I sprayed too much and humidity jumped to 80%, I did that around 1am PST, when I checked it this morning at 9am PST, it was at 78%. I've been checking it with a digital thermometer/hydrometer.

I'm thinking I need more ventilation? The tub currently only has 6 holes.

It depends a lot on your climate. If you live in Florida, you are going to need more holes because the humidity is already really high. In that case, you probably will never need to mist.

Just keep making holes until you maintain humidity around 50%. You shouldn't need to mist a tub for the humidity, it should just be able to hold by itself in a tub.

Very mild climate here most of the year (Oregon). I misted just to boost the humidity and see how well it held, I was more wondering if its holding too well? 2% drop in 8 hours just sounds low to me.

I have had similar problems. More ventilation is all it takes. It depends on the tub size and the size of the water dish you're using. Using a smaller water dish can help keep humidity down. Instead of filling water dishes with warm water, try filling them with cooler water. It will warm up to cage temp, just as warm water will, but not as much will evaporate.

For my BP's large tub, I have 6 holes I made with my largest drill bit. For my BSTP's tiny tub, I have around 20 holes drilled with the same large drill bit. Both cages have the same humidity levels (around 60%).