pig nose turtle

I have a Carettochelys insculpta fly river turtle for few months. It seem the shell has a white patch. May I know how to treat it. Eating and other activity seem normal. 1. Tank size 3ftx1.5ftx1.5ft 2. Turtle size around 4inch 3. Water parameter. 0ppm ammonia 0ppm nitrite, 0.5ppm nitrate. Tank...

Hey, A so cute FRT that I have her last 1 year, she is almost 15cm / 6" shell diameter. Last 20 days I added some big bichers and basses on tank and removed them last night. So last 20 days were so stressful with big new fish and some illness in same time. Lost some fish. Tank was like that on...