I mean colours. And the eucalyptus is at the bottom on the tank. And my spiders have had no
problem with the Eucalyptus.

I repeat:

How do you know you don't have a problem? Have you xrayed the book lungs yet? What are the long term affects caused by continuous exposure to toxins? You do not have a problem YET my love !!

The water held by the pebbles are also at the bottom are they not? The humidity rises from the bottom, does it not? The water vapor collects the toxins as it rises, does it not? The spider takes in fluids through the book lungs, does it not? The water therefore contains toxins, does it not? You are, not purposefully but slowly poisoning your spider(s).

Just a thought...

suppose you make a good point there Uncle. I did create the enclosures before i heard that the eucalyptus.
Didnt see any affects to the tarantula. If the the tarantula is being harmed, would it recover itself after a molt?
Or molt it still be a long term side affect?

Because the book lungs (or at least a large part thereof) are "replaced" during a molt, my common sense tells me that most of the (possible) toxic build up will be removed as well. This is not based on science, just some thought about what actually happens in your enclosure. Because Theraphosa live about a meter under the swampy forest floor, they are heavily dependent on humidity, and probably not only through the book lungs. If the atmosphere they live in is toxic, it simply can't be good.

I was googling for papers on which Eucalytpus sp. has botanical insecticide properties, whether they harvest the chemicals from seed, leaves, bark or wood and exactly how it affects inverts.

Gave up.

Reading words like' lethality' and 'mortality ratio' is plain depressing.

I understand that all sorts of clever folks have clever chemical statistics. You only have to smell it to know it has something weird about it. Also see how a Eucalyptus plantation ignites when a Sparrow farts. There is something that is not good, no matter the sciences.