Great stuff! But no, I couldn't spot the tilapia. Have you ever eaten them? Do they taste good?

I must say, I like the idea having just googled the term. When you change the water in your fish tank, it's got be good for something, hasn't it! And do it on an industrial scale and you could have a nice little, profitable business.

Good luck with your own set up and I think I'll check out some of your links / profile later. :)