ways to atach coral to the rock

There are a few, you can use a 2 part putty that does pretty good. You just find the spot and work the putty on the plug or base rock and then into your rock work. You can simply glue the coral to a larger rock and place it that way.

First question, is this your first tank? Has the tank only been up for 4 weeks or has it already cycled and now if 4 weeks past the cycle?

Good question...4 weeks?

Super glue GEL works great for attaching coral.

If your tank is 4 weeks old then you should not be adding corals. Its just too young and your setting yourself up for failure.

Cycle is the process where your rocks and sand "ferment" as I like to call it. Basically all the stuff (sponges, small corals, worms...) thats on the rocks that died when it was removed from the water needs to decompose. This stuff decomposes into Ammonia. The ammonia is consumed by bacteria that turnes it into Nitrite which is then consumed and is turned into Nitrare.

So if your tank has any Ammonia or Nitrite (Any is more than 0) then your bacteria load can not handle the load and needs to develop. When your Ammonia and Nitrite get to 0 and your nitrates start to rise your cycle is over. This does not mean that your tank is mature and ready for corals.

There are only 2 ways to get nitrates out of your tank. Algae or export. If you have any algae in your tank its due to high nitrates and phosphates. You can either add algae to your tank and grow it (in a refrigium) or your can export it through constant water changes.

Every time you add something alive you increase the bio load and more bacteria neet to grow to off set it. This is why we only add one fish at a time.

Add corals one at a time and give them room. They need to grow and will attach each other. Some corals will kill other colonies if they get too close.

Hope this helps.

O and to answer your question. Crazy glue will bond coral to the rocks. or you can use reef putty for stonies.

Did you mention what this tank has for lighting? Sorry if I missed it.

Aren't there also some bacteria that transform nitrates?

Ok, I will jump in and say yes stop! Its great that your so in to it but you wont be for long when things go wrong. Take a deep breath and READ READ READ. You will get some great advice on here but you really need to read up on all the basics just so you know which questions to ask and what to believe. The person that bought you the tank, do they have experience? I am very new here and wont start to lead you down what roads to take right now but I certainly wouldnt spend more money on a coral or fish right now. Just as a measure on how long some cycles can last, mine took around 6 to 8 weeks. It really depends on a lot of factors and you could very well be ok. Probably not but could be. I would stop and start testing my water daily. If you do not have the knowledge or the test kits to do so the Local Fish Stores can help you. NOT PETCO or other larger retailer, I would go to a REEF STORE and even then depending on who you talk to be careful of what is "FACT". Thats why I say READ READ READ. If you dont have the books and such then you can research online. These are some of the books I have and you may find at a local book store.

The Conscientious Marine Aquarist - Robert M Fenner Start with that one.
What Fish? Abuyers guide to Marine Fish - Tristan Lougher - You want to know what your animals need so you can take care of them.
What Invertabrates? A buyers guide for Marine Aquariums -Tristan Lougher - Tells about invertabrates and some corals - again you have to know the needs of these critters.

Those are a few and I am certain that people will jump in with more and better suggestions. Hope that helps.

also if u add fish to fast (which u already did) your bacteria can not handle your bio load which will cause major stress on your fish and corals possably leading to fish getting diseases and corals dying. reccomend maybe one fish every couple weeks. beat advice has already been said read read read. never add anything to ur tank until u have researched it and are confident you can take care of it