in my 55 gallon cichlid tank? if so where can I get it and what exactly do I use?

also I bought my tank from someone who I think got it from walmart. I want to get blue lights, but I am unsure of the size I need to get. there is two lights on the aquarium ??

Yes you can use sand no bother, you will need enough to give a depth of about 1 inch, you can buy the sand from an local pet shop, or you can get it a lot cheeper by buying pool filter sand or play pit sand, as they are both inert sands, do not use builders sand as it can/will contain harfull chemicals. regards the lights if you have a look on the light tubes you have in the hood allready the size should be on them.

Nevada:

try your local Home Depot or Lowes and look for Silica sand. It's very fine, light in color, completely inert (wont screw with your water chemistry) and is about $5 per 50lbs.

And blue moon lighting is fine. I use it too...very cool. My preference is not to overdo it, though. It is a light after all, so the fish need some dark. I have three small blue moonlight LED's on a 150. Four or five would be ideal on a tank that big.

I think you'll like both the sand and the blue moonlight.