How many tanks will you have room for.
ID the # of
SW tanks and fresh water. What sizes?
40 & 50g tanks might be the choice of
SW tanks
IMO. And since I do
SW, I can only offer opinions on those. My buddy has the 40 & 50g breeder tanks. Usually 6 or so are sharing water and filtration. Gotta account for your fish only tanks which should probably have an amount of copper running thru them. Of course the snails, crabs, starfish, and coral tanks won't.
A lot depends on yur floor space. I'd recommend working very thouroughly with a floor plan, laying out space and tank needs, deciding on safe wiring routines, looking at the plans for a bit, and thinking it through. Nothing like buiklding stuff and then having to sacrifice something 'cause you overlooked something. Kinda like the "measure twice, cut once" rule.
How much space you talkin?
Also, my buddy doesn't do too bad with the stock sales, but really cleans up with maintenance contracts for homes. Two trucks out there almost everyday. Also, he recently put a display tank (with hardy fish) in the lobby of a major movie theatre - w/advertisement. That was good move.
Start looking for seminars and aquarium discussion forums near you. Attend as many as you can
IMO. Good luck.