I am looking to buy 1 or 2 hatchling turtles. Right now I have a 10 gallon with 2 bamboo plants in eco-substrate and a a few guppies. I want to make a turtle tank out of it. Should I break it down completely, or can I keep the eco-substrate and do a water change? The hatchling I am thinking about is the Cooter or Stinkpot. This will be a start up tank for 6-12 months, will then be using a 30 gallon long.