Would it be utterly mad to start off with a reef tank?!

[DrWhy]

Pretty much as the title suggests. I have finally just moved into a house that potentially has space for a good sized fish tank. As a child we had one at home, marine when I was very small but was so much work that dad eventually changed it over to tropical freshwater but I did love the marine tank and as a keen diver I know and love a lot of the tropical marine fish and reef critters. I've always kind if hoped that in my forever home I would have a fishtank.
I know that reef tanks are about the most complicated, difficult and expensive set ups possible but for me I think that it is the kind I would ultimately want. If and this still needs to be negotiated with DH I could afford to get a good setup from the outset of there any chance that a total novice could get a marine tank working? What's the minimum size I'd need to have a decent chance of getting it stable and where do I even start with my research - for example is it better to have a 2nd hidden tank with bio-rock or can you get an effective 'all in one' type system these days?
Just starting to do my research and reading but advice generally seems to be start simple and get more complex as you enjoy it. It seems a shame to start with something that I know isn't what I ultimately want, especially as the resident fish are living creatures who would then need to be rehomed.
Any advice or pointers to good resources would be very helpful. I want to understand just what I might be letting myself in for and if I need to just suck it up and start with a small freshwater tank. My biggest concern is water changes if we have to go away for more than a week once the tank is established.

Yes totally possibly, it's not nessasrily more work at all, it's defiantly significantly more expensive and if you do kill off you tank it's potentially £1000s of fish and coral gone, I think that's why people give up and go back tropical.

If you have a great set up it can maintain itself (to a degree) with RO changes ... I've spent loads of time debating going over to marine but it's like a new world from tropical and it's overwhelming but given you actually know about some fish/reef from diving I'd go for it.

Hi OP, I have a 275litre cube which is now a year old, it was my first tank. Yes, it is very complicated but so rewarding. I would go for something close to 250 as a minimum and something with a built-in sump; AquaReef do the all-in -one systems but you'd need to replace the skimmer as they're a bit rubbish. ND Aquatics do good quality custom made tanks , you'll need to buy your own skimmer and lights to go in it.

Ultimate Reef is a good site to ask questions and share experiences ( although very blokey!). It's good to plan what you want to keep and work backwards; some fish, like Tangs, need a minimum of a 4 foot tank and plenty of fish will eat your corals if you intend to keep them. Remember that most of your fish will be wild caught so it's vital to replicate their natural environment as closely as possible.

An absolute must in my experience is a quarantine tank. This can be very small and simple- go on YouTube for guidance on now to set one up. I began without a QT tank and lost so many beautiful fish to Ich. If you QT any new fish for 3-4 weeks and observe them closely then you can dramatically reduce the chances of some disease decimating your fish when you put them into your display tank.

Happy reefing OP!

Here's a pic of one of my lovely boys to whet your appetite!

Thanks folks!
I had actually discovered Ultimate Reefs just after I posted this and have wasted more hours on there than Mumsnet looking at setups and tank sizes!
Unfortunately until I found some interesting discussions on ultimate reef, I really hadn't realised that almost all fish were wild caught and even more surprising to me that the live rock that forms the basis of most tanks is also shipped over from reefs in tropical regions - I sort of assumed there would be a synthetic option these days. As a diver who's seen the difference between a protected area and a non-protected area I just don't think I could support this until more of it was farmed in some way or at least the supply chain was well regulated enough that I could be confident that what I was getting was from a sustainable source. It seems like that is happening more with corals now but less with live rock and fish.
Sorry, don't mean to sound like I'm preaching. The marine tanks are stunningly beautiful and I'm very envious of the folks who have one but it looks like it's not for me just yet.