I'm going to have to agree with skimmerwhisperer and eww on the size of the tank.
I would say if you are just going to do this as "something new to try out" I would ask that you take some more time before you go out and set up a Marine tank. They take several hours of dedication each week. It's almost like a part time job during the first 3-6 months while the tank is maturing, cycling, and getting a cycle and routine figured out. I'm not trying to scare you away, just trying to save some lives of our ocean counterparts as a lot of the fish, coral, and invertabre we have in our tanks is still wild caught. Enough of my off topic rant...
I would highly recommend you determine what kind of tank you want as everyone else has suggested. If you want to go with a Fish only with Live Rock (FOWLR) tank, then what kind of fish do you want? Do you want a predator tank with triggers, lions, eels, and puffers? Do you want a peaceful tank? This list can go on and on forever before we even start asking what if any corals you'd like to add.
Do you want any Tangs? <---- If yes, because they are wonderful fish, I would look at getting a 6' or 8' long tank. From experience, I do not desire to own another tank that's over 24" tall. I would prefer more width than height as all my fish stay around the same depth when the swim around. On top of that, the wider your tank the more opportunities you will have for aquascaping. Down side to a wide tank, is that you will have to keep the water extra clean.
There are also different types of "centerpiece" fish that people will build their tank to cater that fish and the rest are just fillers to make the tank look full. One of these fish is a Blue spotted Jaw fish (BSJ). They are very pretty and cool fish. They require an aquarium with a deeper sand bed so they can build their burrows.
There are pros and cons to running a bare bottom tank (no sand), 1-2" of sand, or a Deep Sand Bed (DSB). It all really depends on how much time you're willing to put into your set up.
I would say it should be a requirement that you get a tank with internal overflows, or drill the tank. It makes everything a lot easier and there is less things to fail.
One thing is for certain with keeping a Marine Fish tank. You want 0 Nitrates, 0 ammonia, and 0 Nitrites detectable in your tank.
You can ask 20 different people that have successfully kept Marine tanks for 10 years each, and chances are each one will give you a different answer on how to get it done. Is anyone wrong, no, they are all successful doing it their way. Since there will be a lot of different opinions on what to do and how to get started, (as evident already by what size tank you should start off with
) just try to find what works for you, and stick with it.
I say you should start with a bigger tank for the following reasons:
You will not have to upgrade as soon.
It takes longer for something bad to happen
Big pretty tanks are breath taking
You can put more stuff in a bigger tank & keep bigger animals
The bads of big over a small tank.
Cost more (Aquarium, salt mixes, additives, lights, etc.)
The Main pro's and con's of acrylic vs. glass
Glass:
Heavy
Cheaper
Harder to scratch
Silicone can fail and cause leaks
No insulating characteristics
Acrylic (Plastic)
Lighter weight than glass
Supposedly stronger
Scratches super easy
Has a little bit of insulating characteristics.
BIG $$$ for a big Acrylic tank.
Hope this is helpful to you,
And WELCOME to Reef Frontiers.