Adding multiple remote fuges... questions?

[xtlosx]

Hey everyone.. So I'm looking to expand upon my natural filtration for my 150G tank.. My fuge just isn't large enough, and I am lucky enough to have a little room with a door right next to my DT (this room has my water softener, etc so it's rough).... Here's my thought. I welcome all ideas, and suggestions!

I had t'd off access from my return line (one for my gfo\carbon reactor) and another that is not in use. My return pump is heavily throttled so this would actually let me open it up much more. I could feed from my return to this room via 3/4" pvc (I have local plumbing expertise) into this little room. My thought initially was to have a shelving unit, and have several 10-20G tanks stacked.. The first where water would drain would just be a 10G tank with chaeto, a koralia, and a light. The chaeto could tumble, and grow, exporting nutrients all day long. This tank would overflow to a tank on the next shelf, which would have a large DSB for nutrient export. This tank could overflow to a tank underneath it which would just have a bunch of live rock.. This whole thing could gravity drain back into my return\drain area through 3/4" pvc..

Questions..

- Does the chaeto tank sound ideal for it to grow? Would it make sense to grow caulerpa or anything else , or just chaeto?

- How deep does the DSB need to be, and how large for it to be efficient? I could as large as a 20G tank possibly..

- Anything else I could do to make this efficient for nutrient export?