i also started w/ a undergravel filter and
cc, but after reading much about it decided to switch to a deep sand bed for two reasons. The
cc can be a big pain to clean and can produce lots of Nitrate later on. Two, the
dsb houses beneficial bacteria which acts as a biological filter. So I suggest that you change from the
cc to a
DSB.
Do you have and Live Rock? It is also a very good source of biological filtration and almost necessary to a
SW tank. It houses lots of bacteria and little critters and also gives the fishes place to swim around and hide in.
What kind of a tank do you plan to have? fish only or one with corals?
To get your tank to start cycling you should go to the grocery and get 1 RAW shrimp and throw it in your tank. That will get the ammonia going which is the start of the cycle.
I just started my first tank about 6 weeks ago and had all of those questions and many many more hehe. I suggest that you just read lots and lots of posts on this site to learn as much as you can. The people here are very very good at this and are great at answering questions!
If ya wanna PM me any questions about startin your tank up feel free to as i just went through it and have learned a lot =)
Good luck!
Ross