i say do it. you only live once you may as well enjoy yourself
it can be a lot to take in, but deffo worth it. i should know, i was in your position 18 months ago...
basically setting up a sw aquarium can be as simple as adding salt to your water and leaving it to cycle. most people will recomend the use of live rock in marine aquaria, and i agree. it does help filter your tank. it also looks cool... getting the biggest tank you can afford is a good idea, but money doesnt grow on trees, and we have to use what we can. i started on a 10 gal, it can be a PITA but just keep an eye on it you'll be fine.
if you go down the live rock route, you will want 1-2 lbs per gallon. i suggest you do, as you can always get rid of it if you dont like it, but adding LR to an established aquarium will cause it to go into another cycle, unless that is its you get fully cured LR... but ist easier to get it out of the way first and be done with it.
you'll need some things to start.
*hydrometer/refractometer
*1-2 lbs of Live Rock per gallon
*sand, enough to cover 2". i have my sand 4"+ at the back so it slopes to the front. wash it first. you can get live sand, dont wash this though
*Hob filter rated to around 200 GPH
*powerheads
*heater
*Marine salt
*tester kit
*prawns
get your hydrometer/refractometer, mix up some salt water ( around 1.023sg) and half fill the tank, so when your in the tank rearranging the rockwork it doesnt overflow... then get your hob filter rated for around 10x tank volume (approx 200 GPH), heater, and a few powerheads for extra flow, and place them in the tank, now add the sand around the rockwork. i use playsand, i have no problems with it. its cheap too... so its all good.
this way any burrowing animals wont cause your rockwork to collapse as they dig. top off the tank with some more salt water, and turn everything on. you want to aim the powerheads so they dont leave any spots trapping debris. so you'll have to tweak their position.
once the tank is running, i.e. everything is in, add a few cooked prawns to kick off the cycle, basically leave for a week, then start to monitor the params, in about 10-12 days you should be good to go.
you can have a protein skimmer too, but its not an essential item. i had my tank running without a skimmer for about a year with no problems. the only reason i use one now is because i was given one a few days ago for free. its only in my tank as i have a lion fish (huge bioload), so it just removes most of its mess. if i didnt have the skimmer i would just do more water changes. so its your call if you want one.
id also look up fishless cycleing, and drip acclimatisation on google. for lighting id decide what type of tank you want first. if you want corals check out the corals and inverts section of MFK, theres loads of info in the stickies at the top of the page. also search for begginers marine fish. avoid damsels if possible, theyre basically cichlids of SW. add them last to the tank if you want them. also avoid mandarin gobies, they need loads of live food, a 20gal isnt going to produce enough critters for it and you'll have to buy them, which will be expensive in the long run.
welcome to heaven my friend, also welcome to hell when something goes wrong or dies... but when it hits the fan, thats where the forum comes in handy...
if you have any questions just ask. someone will be able to help.
