lopsided floating with my red eared slider

Question
i have raised a number of turtles in my life and i recently transferred my red eared slider from a ten gallon tank to a thirty gallon tank.  i have noticed that when he floats in the water his left side floats significantly higher then his right making him float diagonally.  i am just concerned if this could be a health issue out of the other turtles i have raised this is a first.  thank you for your time.

Answer
I don't generally answer water turtle questions and posted some good sites in my profile for you, but...

Tilted turtles generally have a lung problem going on- pneumonia, for example. It may be infectious, but it also often shows a problem with the basic cares.

I noticed, for example that you are keeping it in a 30 gallon tank. The rule of thumb for water space is to offer 10 gallons of actual water for every inch of shell length. A partially filled 30 would be about 20 gallons, or enough for a 2" turtle. Over-crowding and improper tank size can easily contribute to health issues.

You can try sites like http://www.redearslider.com http://www.austinsturtlepage.com, or http://www.turtleforum.com for more help.