i'd agree. it's definately a big piece, but it doesn't have anything on it. I don't see any coraline algae (purple) or anything. Def. not worth $100
and dapaman. No additives. Doing frequent water changes (i'd suggest 10% ever 2 weeks for a reef tank) will replace all the necessary elements.
As far as your lighting, let me make this very clear. There are many different types of lighting and there are many different types of corals. Corals generally fall into three categories - soft corals (such as a colt coral, mushrooms, etc); SPS (smally polyp stony) - these are hard corals. they have polyps in them, but these polyps are so small they show the hard "housing" which is why it's called SPS; and LPS (large polyp stony) - these are corals that have large polyps that you can see, such as polyps, zoos, etc.
ok, now lighting also comes in different types. I'll list them from lowest intesity to highest: normal output (NO - these are just normal florescent lights), power compact (PC), very high output (VHO), T5, and metal halide (MH). Soft corals and LPS generally require PC lights only. However, SPS and anemones generally require MH. So saying "our lights can support corals" doesn't really tell us much.
colt corals don't require high intensity lighting, so if you have PC lighting you'll be fine. Just make sure you always research any coral before you buy it to make sure you have the proper lighting to support it.
Hope i don't come off rude or forceful, because i'm not at all
, just want to make sure you do the best thing for your tank, and you waste as little $$$ as possible. This hobby is expensive enough as it is so there's no need to go wasting $ if it's not necessary.