Worms dying after mixing them with old compost

Hi,
I've just killed some hundred of worms

I had quite a big chunk of worms in a vermicomposter in my flat where I was adding some vegetables from time to time. Suddenly it started to smell bad and when checking the compost I couldn't find any worm.

Since I live in a flat I took all the liquid from the old compost and left it in the back of the vermicomposter hoping that I could later recover it when I grew some new worms. I order some new red worms and left them in the upper part of the vermicomposter for a week without adding any other food than what it came with them.

A couple of days ago I started adding a bit of the old compost next to the worms so they could decide to jump if they liked. Some of them started to do so. Yesterday after making sure that everything was fine with them I decided to put a bit of the old compost under the new compost with the worms. But today after coming back from work I saw that there were no worms at all I could just find a couple of them (from hundreds) and they were dead.

I've seen the old compost contains some flies and small white worms (maybe the flies ones) which may have something to do. So far I understood it's better to throw all the old compost away and start from scratch although I wanted to avoid this since cleaning it in a flat it's probably not the best idea unless I want my girlfriend to kick my ass.

I just wanted to hear opinions from the community about what could have caused the problem so I can avoid it in the future. I have to admit I feel bad about killing animals even if it's by accident.

Thanks

I read last year that "One worm's poop is another worm's poison." Not sure if that was your initial (and subsequent) problem.
Over population is a real concern. As is high temperature.
Are you removing your old casting on a regular basis?
Worm Casting Tea is wonderful for house plants and garden plants alike.
I was selling Work Casting Tea at our local Farmer's Market.

hmm, If I understand you correctly, you had a batch of vermicompost go sour, which killed worms initially, then you bought new worms, and gave them some of the sour compost, which killed them again?

With the fly larvae, and the sour vermicompost, are you certain you never put meat in the composter? Meat will cause both of these phenomena. Alternatively, the first batch of compost may have gone anaerobic while you were waiting for new worms. This would explain the second die-off, and maybe the first. Often compost will go anaerobic when too much water is in the system.

Thanks for your replies.

This weekend I cleaned and disassembled the vermicomposter and found the bottom part full of fungus (all white) that probably caused the problem. I've cleaned it and will start it again with new worms.