Reef Builders - The Source for Reef Keeping Information

Hello everyone,
My first blog/post....but I wanted to share some pics of my tank (150) that I have owned for about 4 years now. It has been geat and the best hobby I could invest in. I do have a question that I would appreciate some help with...and that is nitrates....I never had a problem until recently and nothing seems to work....its affecting my invertebrates and I have lost a couple of stars, shrimp, etc...also whenever I add snails they seem to last for about 1 week.....everything...