This is in 500 or so gallons of water between all of the tanks and is based with 25-30 year old live rock that has never been dry. I also run a ton of carbon and the water has to be kept pristine. Anything outside of that, and I have issues with the nems wanting to fight.
Not saying that this is needed, but I know when my carbon is about depleted, as the nems react to each other. The mags will ball up and the haddoni will attempt to curl over and sting every other nem.
In regards to setup, it is actually 2 tanks. One is a mangrove/macro lagoon and the other is mostly nems with a small section for some zoas frags.
Here are some pics of the setup. A few of the tanks are under the other tanks and there are 3 off tot he left side that are not in view, but all runs to the rubbermaid trough.