The problem with the internet is that there is so much contradictory anecdotal info that it can be confusing. Having a solid foundation in understanding basic chemistry and the various types of filtration that occurs in tanks provides for a solid foundation of understanding. A book provides for this, for the most part, where you are given information that connects from A to Z. Unfortunately, some videos or articles tend to start at C or E and go to M, while skipping G and H. The point being, getting some information w/o knowing limitations isn't necessarily helpful. I find that many books cover the basis and thus allow someone to better interpret the information posted on forums or videos. Be able to sort out those that are helpful from those that aren't. And you can't beat a good identification book. The corals book posted is fantastic!