hey everyone. i was quite curious because i read that you can buy purified water for your water changes if so is there any specific kind? and is it recommended. because i currently only have tap water sources. and i just have the water treatment that comes from wal-mart. not exactly sure of the brand. the question about that is how long do u have to let the water sit before you add it to the fish tanks. i just wanna make sure i know what to do when i'm faced with doing a water change. (just meaning water change for a 10%-50% water change) thanx.