Just put the new rock in your tank and allow it to finish curing. There will always be a slight cure even with precured rock.
No you wont be able to simply put a T5 into a standard fixture. Two different animals.
Like Carl has suggested... just take your time and save up for a SWEET fixture. Don't do like I did and buy THREE different ones before I was satisfied. I started with standard "Petco" fixture. Then let the LFS sell me a single bulb PC unit (when I knew I wanted more). I was happy maybe a month. Then I decided I wanted more so I went back and bought a Dual bulb fixture (again one he suggested since he had it IN stock). Maybe another month until I decided I wanted MORE so I bought a whopping 130w fixture and really got serious about my reef tank.
Go big bro!!
Welcome and HAPPY REEFING!!
