red ear slider swimming

Question
I have 2 read ear sliders which have been doing well in their tank, filtered water, heated, basking light and UVB.  I feed them pellets and Calcium supplement.  Recently, the larger appears to be unable to dive to the bottom of the tank as ii is too buoyant.  Do you have any suggestions?

Answer
Hi Jeffrey I sent this answer to you already and I think somehow it got lost.
It would seem that your turtle has a upper respritory infection. Please tell me about hte care he is getting. I need to know about the set up, foods, light heat etc. Please let me know asap so I can assist