1. Is a 29G to small?
A 29 is the smallest I would go. Bigger is more stable, and easier to care for than smaller tanks. You'll need to go very slowly, and monitor things like salinity regularly until you establish a routine maintenance schedule.
2. What kind of filtration will I need?
Live sand and live rock work well. You'll want about 4-6 inches of sand, and then about 30-50 pounds of live rock.
3. What's up with this live rock thing? Will I be able to get some?
Live rock is porous rock that has little critters, algaes, sponges, ect growing onit's surface, in addition to nitrifying bacteria. Any reputable fish store should carry live rock, or you can order it off the net.
4. What about corals and other plants?
Corals are not plants--they are animals. However, corals have different needs from fish, so you should research specific types of corals and make sure you can meet their needs. Lighting is a big one for most corals, but many fish will eat corals, so you have to plan carefully.
5. How do I make it salt in the first place? Do I just add salt?
Saltwater for SW aquariums is made using s ynthetic salt mix (such as Instant Ocean, Red Sea, Tropic Marin) that contains mroe than just salt. Trace minerals and buffers (to raise and stabilize pH) are a must. Depending on what else you have in the tank, additional additives are used (for example, calcium is very important for hard corals, and must be increased with a supplement. The mixes don't contain enough). Otherwise, most people mis their salt in a separate container, and heat it, then add it to the tank. Not needed on initial setup with no critters, but crucial (IMO) for regular water changes.
6. What kind of levels will I need to have to keep a marine tank. PH, amonia etc....
pH is usally around 8.6 or so. It's much higher than a planted FW tank, but close to a african cichlid tank. Ammonia, nitrites should all be zero, nitrates should be low, depending on what you have. For corals, nitrates should be VERY low--under 20. For fish only, depending on the fish, below 40 is pretty good. Specifc gravity (hydrometer, used to help determine salinity levels) of about 1.024-1.026, lower if FO. Test kits for copper, calcium, phosphates, ect are available, and needed depending on what you stock.
7. Any special lighting required?
Again, it depends on what you want. A reef, yep, you'll need extra lighting to the tune of 4+ watts per gallon, probably VHO, metal hallide or power compacts. Fish only, doesn't matter, whatever lighting you want for personal viewing (this will kill off most of the critters on the LR, but it will still function as a bio-filter).
