Thank you all for your comments.
Blueblue! I guess you are the only one who might have a real tree near your house
i was asking myself if some of my tank have problems.As to decomposition rates, I have leaves in a 90% RO tank that look like I dropped them in yesterday, when they've been in there for 2 months and I have leves in a tank that is 50% RO that decay completely in a month.
haha... actually, there is one near my home and one near my office.
I used to pick up some in the winter, while i recently acquired 500 pieces of this leave from a friend who ordered a full box of thousands from Indonesia... so, i have plenty to use for quite a while, hehe