Great post otherone! I must say your points are spot on. To the OP, being that your system has only been up for a month I wouldn't add much at this time. When you do add to an immature system you need to do it systematically. You must allow the system to compensate for each addition, I would say no more than 1 fish at a time. Monitor your condition frequently, at this stage your tank will still experience parameter swings. Adding sand from your dad's tank didn't help, if anything it hurt. This concept of live sand if ridiculous for the most part. While you may have moved small portion of beneficial bacteria, most of what you put in the tank with used sand is detritus. As stated in the above post, you need to research and research, when you think you've researched enough you probably haven't. Some of my first critical mistakes in this hobby (Which almost drove me to quit) were because I took the advice of everyone on aquarium forums. Don't get me wrong, there is a lot of knowledge to be gained on sites like MFK, just verify everything with some research of your own.