after 3 years of having a healthy colony of worms, they all died last month I was very sad, because before I left on my vacation, they were doing well, and when I came back 3 weeks later they were all dead.

I believe what happened was they drowned. I was cleaning out the bin (the stuff in there was soup), I noticed that the 4 holes at the bottom of the bin was clogged up like a hard calcium deposit.

so make sure that you have enough holes for the tea to drip out so they won't be drowning like mine did

I've since gotten more worms and started another one, but I'm so paranoid now.