Octopus - Size of Tank needed?

[JakeMallowFilms]

So I'm looking to buy an Octopus from Liveaquaria: http://www.liveaquaria.com/product/prod_display.cfm?c=497+500+1719&pcatid=1719

I've had people I know who have had success with these cephalopods in small systems. I'm wondering if I order them small, how small of a tank can I have with it? It says on Liveaquaria that the minimum tank size is 70 gallons. Yet, they say for most tangs nothing less than 180 gallons. I've seen many people keep tangs successfully in 75 gallons. I just really want something small, that I can enjoy. Like an AIO possibly.

Currently I have a 75g mixed reef, and I'm planning on buying a smaller tank, for the octopus.

Thank you,
JakeMallowFilms

 

[Betta132]

Problem is, it says 'assorted'. You might end up with something huge.
Also, what setups have you seen with a tang in a 75g? Was it a young one?

 

[Lmecher]

I had been keeping O. briareus and A. aculeatus in a 50 with no problems until I received O. vulgaris from my supplier. I found out just why a large tank is imperative. I had to scramble to get my 120 up fast. With arms that grew to 18" he was a monster. They produce a lot of waste eating live food. I had an ammonia spike that made me move him a little earlier than I had planned. Do heed the warnings and recommendations on tank size or forgo keeping octopuses. When ordering octopuses online, it's a crap shoot. You never know what you're going to get. They are very difficult to identify.