I prefer nature simulating enclosures. I think you will find however, with crocodilians and tanks, simple is better. I prefer not to disrupt filter flow. It inhibits the cleaning of the water and even heating. I wouldn't invest to much resources in a tank that he will not be in long. With proper care, he will soon need more than a tank. My larger enclosures Have plastic plants, etc. I even have had box turtles share an enclosure. They were seperated by a partition. The humidity was not a problem in an open air enviroment. Box Turtles from the south east should handle humidity well. They are even hard to find except after spring and summer showers. In a tank it would probably be a problem. There is a limited amount of air flow. I prefer to have more space and air flow, before I make the enviroment any less sterile. Crocodilians are very durable, but I think a hatchling is still a hatchling. When they are small, I am careful that they ingest only the food I offer, The water very clean, even water temperature, proper range of land temperatures, water/land amount, uv lighting, and little more. I like to "play" as they grow. I have had only a few hatchling crocodilians, and I am satisfied with what I have. I am not an expert. Just sharing my thoughts.