I wonder if this is really working as you think it is. And please don't take any offense. I'm not attacking, I am just reading what you're saying here and here me out.....
You're measuring humidity levels at the bottom of the enclosure (based on the picture you provided, it looks like your humidifier is blowing it's fog into the bottom of the enclosure) where your fog is entering the enclosure. This doesn't seem right. Of course, you're going to get really high humidity levels at the point of entrance.
Where you probably should be measuring is as close to where your chameleon is when this fogging is taking place. The reason for this is because I have multiple sensors in my enclosure and they will all read differently even during fogging ( my enclosure is also 36"x24"x48", so a bigger size will certainly have a higher chance of different levels throughout the enclosure).... simply because (especially in an open screened enclosure) the fog isn't contained, and the enclosure is aired out well (which is a good thing unless you have severe issues reaching proper humidity levels). And as you get lower into the enclosure (when lights are on), temps lower, and humidity rises, gradually. Especially depending on the plants in the enclosure, and how that's all setup.
So... while the humidity is higher at the point of entrance, your humidity is likely only affecting the area that's actually being hit by the fog (at least for the most part), and not so much where your chameleon is physically hanging out. This is why our foggers are always pushing fog from the top of the enclosure, not the bottom. If we placed them at the bottom, our chameleons would never gain any benefit from it and wouldn't be affected by it at all most likely (good or bad). Unless of course, our chameleons were sleeping or hanging out around the bottom while the fogging is occurring
Your fog looks like it's not rising. as it should be. Applying fog from these machines, I've only ever seen the fog fall. Which leads me to believe that unless you have this unit pushing the fog above your chameleon, or at least at the same level, hitting your chameleon horizontally, it's likely not even doing anything in this situation.
I also do wonder why you need to quickly hydrate. Even if you're personally catching these chameleons out of the wild, what is really the purpose of that? If you set up your husbandry properly, your chameleon should be getting proper hydration. I don't see why you would need some kind of significant boost.
I'm assuming of course, but if you're wild catching them yourself, you're likely not transporting them very far. Unless, you're having them shipped to you from someone else catching them in the wild? But even in that case, proper husbandry should be sufficient. I don't see how overloading hydration would help the chameleon be less stressed. That significant change in their life is going to be stressful initially regardless.
side note: On top of it hitting the bottom, it looks like in your picture, it's not even pointed in the middle of your enclosure, but the fog is only hitting a bottom corner of the enclosure. Which further leads me to believe that this humidifier isn't really doing much of anything for the rest of the enclosure, above where it's actually hitting.
Regarding my entire thought process on the humidifier, Vicks specifically even recommends placing these humidifiers HIGH not low (again likely because the fog will fall but won't likely affect anything above it much), and centered in a room as much as possible.
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