dayne wrote:mine is allready moldy and covered in slime thats not a good thing after about 6 months you can do what you like ill do what i like it so simple if water leaks out all day its too much it just dosnt dry out up here our humidity is over 60% most of the year some trees yes others no
Agian Dayne this makes me think there is something else going on here. Any medium will stop drianing something as little as 10mins after getting watererd(or rained on) Water will only leak out all day if water is entering the top of the pot all day. The pot will take up all the water it can and excess runs out the bottom. This excess equalises in a matter of minutes and is no noticeable difference from medium to medium.
No matter how much water Diatomite holds it will not continue to seep out water. It will only continue to release what excess is applied to the pot same as any other medium. It may look like water is continually coming out the bottom of a pot when the bench stays wet but believe me this is not possible.
Take one of these trees water it and let it drain for 20minutes then put it in a drain tray to see if anymore comes out and you will see what I am saying.
But as you say your trees in Diatomite seem to be waterlogged

I always say a tree that uses lots of water shows it is healthy. I can have a tree in the best draining mix but if it is not healthy it will stay wet. I can have a healthy tree in a crappy collapsed mix and it will take as much water as I can give it.
I wonder if there is a health factor that is only present in the Diatomite that is causing this issue.
Maybe the 100% diatomite mix is being under fertilized. Walter states a medium like this should be very heavily fertilised. The trees in 70% debaco would be getting the extra nutrients from the composted humus. More nutrients more root and shoot growth means more water used. I would be checking and comparing the root systems of the debaco to the diatomite.
It is sometimes to simplistic to jump to an obvious conclusion.
Used Diatomite trees where water logged must be that diatomite holds too much water. I see it hapen so often.
Watered banksia with seasol. Banksia died, Seasol kills banksia People will go out and say this instead of buying a few $3 banksias and seeing if their theory is correct.
Walter gives a good example here that is somewhat relevant
http://walter-pall-bonsai.blogspot.com/ ... -myth.html
It's too bad your in such a hurry cause the stories I could tell you, Bushels and baskets of stories, hole crates full of stories. But if you can spare a moment I will tell you one story.