I made sooooo many mistakes on my entry into this hobby that it's completely embarassing. I figured that if 3Reef members saw some of the mistakes we've made, you will; A) Learn from our mistakes and, B) Make better choices than we did. What are some of your mistakes? Here's a few of mine. Didn't buy a good all around book for the basics. Started too small. My first tank was a 9 gallon Eclipse with normal output lighting and hang on back mechanical filtration. (Larger tanks are more forgiving of newbies mistakes. It seemed fine to me because my wife was told that tank was fine which leads me to my next point....) Looked for answers from people rather than looking to understand the reasons for those answers. (If you don't understand the basics of lighting, filtration, the "cycle", coral biology or fish biology, this is going to be a VERY frustrating hobby for you). Didn't understand the pros/cons of various sizes of crushed coral Vs. various grades of sands and how the maintenance of them is very different. (For instance, if you have crushed coral, expect to need to vacuum it because it traps detritus/uneaten food). Didn't research livestock on my own BEFORE purchasing it and trusted the person at the LFS. Not only did I have a baby horseshoe crab in a 9 gallon not knowing how big it would get, it was also in a very course crushed coral substrate.....it died. I didn't find a real mentor. My "mentor" was a guy named Brad who was very helpful at the LFS which I went to EVERY Saturday. After a few months of frustration and me asking him questions every Saturday, a LFS employee took me aside and said, "Don't listen to Brad. He doesn't even work here. He just hangs out here during the weekend, messes up people's tanks, and then tries to get customers to subscribe to his maintenance services. Haven't you noticed that he can't ring you out?" (I hadn't). Tried to do a fairly expensive hobby too cheap. Example, after finding out I needed a better filter for a tank that was not all that ideal for marine tanks, I looked at two models. One was about 30% more. That's the one I really wanted and needed, but I chose to save the money and bought the cheaper one.....then 3 months later, went and bought the one I should have purchased in the first place. In other words I spent substantially more than if I had purchased the right filter in the first place. Did I learn my lesson from this mistake? Nope. I upgraded my lighting twice too. All I accomplished was spending more money and starting my "equipment graveyard" in a closet. I didn't use the Internet to my advantage. Granted, things were different back in the days of Usenet Newsgroups. You guys pretty much have it made. Many more people in the hobby, forums with excellent search engines, photo's, etc. I'll add more to this later....just wanted to give it a start.