Not to offend you cbenn (I have a feeling its going to anyways) but you need to seriously do some research on the hobby if you dont know what some of these crucial and fundamental aspects of keeping a marine tank are like running carbon or having proper testing materials. You need to understand the requirements that need to be met for these animals to survive. Ammonia going from "not good" to "ok" simply isnt acceptable. Its like saying the air for your dog to breathe went from not good to ok and still wondering what is causing him to pant. obviously its the crappy air hes still breathing, ya its an improvement but the problem isnt solved. You need to slow down and do at least some research or the rest of your fish WILL die. And its bull when people try and blame pet store owners, sure they sold it to you but you also bought it without a clue as to how to care for it. Bottom line YOURE to blame. You also should probably appreciate people trying to help you instead of getting mad because someone tells you something you dont want to hear.