I just set up a 29h tank yesterday. I got 30 pounds of sand for the tank, one 25 pound bag and one 5 pound bag that were 2 different brands. The sand from the 5 pound bag didnt really mix with the other, and is sitting on top of the other sand. It kind of looks like its floating just above the other sand. I tryed mixing it up on the bottom and all the sand from the the 5 pound bag will float up and then sink back down. Do you think this is a problem for the tank, anyone heard of something like this and know how to fix it?