I have a 10 gallon freshwater aquarium that I am plan on keeping a few guppies and a couple of plants in. The filter I have is the Tetra Whisper IQ. I was wondering what the best media for mechanical and biological filtration would be in my situation. Most of what I've read has said that chemical filtration isn't necessary unless there is a short-term issue or you are using tap water (which I will be). I don't know if this is important in deciding what to use or not, but the water I am using has tested 0ppm for nitrate, nitrite, and chlorine. It tested somewhere between 150-300ppm for hardness, 300 for alkalinity, and somewhere between 7.8-8.4 for pH.