[ponokareefer]

-I'd buy dry rock instead of live rock. You can get a couple of pieces of live rock from people who are selling it on canreef to "seed" the dry rock. There are a couple of reasons for this. I wish this is the way I had gone and is definitely the way I would go now for the following reasons:
1. It is way cheaper than buying liverock from a store. 300 pounds is going to cost a lot from a store. If you do find a lot cheap from another reefer, #2 is the reason I would still go with mainly dry rock.
2. You avoid bringing in things you don't want into your system. These things could include: killer crabs, killer mantis shrimp, aiptasia, majano anemones, red bugs, bad algaes. When buying the live rock from fellow reefers, you are going to want smaller pieces that you can fully inspect to ensure they don't have these on them.
Dry rock will make your cycle time longer, but it is definitely worth it.

-Sand is a personal thing. There have been a lot of reefers that go completely without sand and have awesome systems. Sand is needed for some things to live though, so you need to decide what will work best for you. You can just ask for a small cupfull of live sand to "seed" dead sand rather than going with all live.

- You could get away with less than 300 pounds in your main system. Sand will help, but the main issue will be how many fish and creatures you have in there. The more fish and creatures, the more rock you should use.

-I would use RO water for water changes and top ups. You introduce crap into your system otherwise. For the initial startup, I just used tap water and cheap salt though.

-U/V and CO2 are not necessary. A chiller is only necessary if you go with high powered metal halide lights or if your house runs quite hot. I would take a look at the new LED lights out there. They are more money, but you are saving on your electric bill, and the cost of replacing bulbs every year. They will pay for themselves in a few years. Also, LED run the coolest of all bulbs, so a chiller wouldn't be necessary unless your house is hot. I already have a light fixture otherwise I would be buying one of the new fixtures. They each have their own benefits.

-Do not use bioballs in a reef tank. Bioballs turn into a nitrate factory and your system will suffer a lot. You can use live rock in the sump though.

You are going to have a lot of information thrown your way, so I will leave just one more tip for now. Get a lot of flow from powerheads in your system. Koralia's are decent and cheap and create a lot of flow, Tunze's and Vortech's are the best, but you are paying a lot of money.