Northern water snake and red eared slider?

i caught a northern water snake at a creek about 8 months ago(sometime in august) and when i caught it it was about 2 feet. It is currently 3 feet. I have it in a 29 gallon tall tank and have the bottom 3 to 4 inches filled with water. I also have a small red eared slider that is about 3 inches with i caught sometime near when i caught the snake but at a nearby pond. in the tank i have small pebbles, a basking rock, a waterfall (the basking rock and waterfall both provide dry land) and some fake water plants. I have a filter and a eater too. I have two heat lamps and a fluorescent bulb. I feed the turtle pellets and the snake 2 dozen feeder fish a week ( and some times small blue gill). With this information i have one question. Am i doing all thins right, and also please give me extra information i might need if necessary. thanks