First off, welcome! Listen to the folks above, they have a lot of experience in this. For my 2 cents, you mentioned that you change your T5 bulbs frequently........how often is frequently? Other than the possible copper contamination, frequent changes in the lights can stress the corals.
Also, I would recommend the $20 fee to become a full member. You will get access to ALL the forums that way......including the For Sale/Trade/Free section. In addition to the good advice you'll receive on this forum you will also find outstanding deals on livestock and equipment, to include free stuff. The members here are great and will help you get your tank right and eventually restocked with corals and things.