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My opinion: I think you should learn with your 30 gallon tank. Keep invertebrates such as crabs. Get a featherduster and a few other smaller inverts and live rock. Raise lots of amphipods. Learn how to do tests and water changes well. While you're doing this, look into the tank and equipment you'll need for the next stage. Price all the equipment and note shipping charges.
When you are ready, set up a 50-75 gallon tank with live rock and the filtration you need. Let it cycle for 3-4 months. Then get a bimac.
I'm with Nancy on this one. Get some practice with other marine inverts then go for the Bimac. I've never had one (cos I live waaaaaaay down south) but they seem to be about the most keeper friendly (excepting our Squidgy of course....he knows how much we like to play get the octi out of the drains, the neighbouring tank, the walkway, the other neighbouring tank, the drains........so he tries to play it most days ....just for us!!)
Iv been doing this for about 5 months but Iv read up alot of books and threads looked on the web alot to I now alot about the marine tank and am just geting in to octopus so I have done some water tests and water changes but more practice would help alot thanks