I had missed a lot of these comments. Some good ones too! I think 5 aros is plenty! I'm not into the overstocked tank look, period. That's the only reason I wouldn't go with more. I would rather see fish with lots of swiming room and happy than to see a ton of fish crammed in a space. I'm still debating on the rest of the stock. I was thinking discus at first, but they're so fragile, I think it would limit what else I can have in there. ATM, I'm thinking Oscars. That would provide a LOT of interest in the lower part of the tank.
One other thing regarding a big tank and filtration, on top of cost for the filter is the sq.ft. req'd for some people's thoughts on how big it should be. I've read some rediculous sizes for w/d's suggested. I think most of them are just WAG's that er on the side of caution to an extreme. I've heard of 15x turnover on tanks recently, which I still think is absurd!!! It used to always be 2x per hour. For 15x turnover on some tanks, you would have a turbid environment, which is not where these fish are from. They're in slow to still moving water. If I put the suggested 15x turnover on this thing, I think I'd have some PO'd aros.
I've been keeping tanks with 2x turnover for around 20 years, and I've always kept 0 wastes readings and kept low nitrates with water changes. This thing will have a constant supply of fresh water at a rate to equal 20% per week, so a 2x or 3x turnover will keep it in check, so long as I keep the stocking down, i.e. 5 aros, not 30.
I have fully investigated the feeding costs, and am more than prepared to keep these buggers too.