TK... this is just my opinion, but I think you may be overly concerned about the toxins. I'm not saying that there aren’t things in our tanks that can damage or kill... but that’s nature. If you shy away from everything that produces toxins you will most certainly end up with a whole wall of "temp" tanks with a single species in each. If that fits your picture of a great tank then you are on the right track, but if you would like to have a small sample of the living reef then you will undoubtedly have to mix different species together.

I have seen zoos in every sort of tank. I myself have a zoo colony that has recently allowed an arrant blue mushroom to grow right up through them. I've got an SPS, next to leathers, a hammer only inches away and they are all surrounded by zoos. If they seem to be bothering one another I will move them or change the flow of water. If I don’t take care of it they will…

You should make the tank that you picture in your mind as the "perfect tank". If that means no mixing then I say “go for it”, but if you want something more like nature then don’t be afraid to mix the species that others have had success mixing. You might find that micro managing the reef is a big part of the fun of it!!!

just my 2¢