Shell Problem

I’m new to the group and not as experienced as the people already in here. I need technical advice and moral support. My dbt which is about 3 years old developed a mild fungal infection over the winter. I thought it would quickly resolve itself with a few povidone baths and some basking. The opposite seemed to happen very quickly while I was focused on other issues. I inspected him(or her) more carefully about two weeks ago and the fungal infection had spread to several areas on the carapace and I think as well to the plastron, though it doesnt look the same there. I had to remove several diseased scutes. Some had water trapped underneath and were clearly a breeding ground for infection. I am bathing him in diluted povidone one to two times per day for fifteen minutes. I am keeping him out of the tank overnight and applying neosporin antibiotic alternated with lotromin and with a night of no treatment–to let the air get to it. I am letting him back into his (small) pond during the day which is equipped with an Aqua UV clarifier and gets a lot of direct sunlight. he spends most of his time out of the water on a shaded land mass within the pond (Is that normal?). There are other turtle species in there with him but I felt the uv light might mitigate possible cross contamination. In some areas where the scutes peeled off the tissue underneath is smooth and white. I am assuming this is live tissue and needs to be left alone. In other areas the infection seems to have only affected the top surface of the scutes. (He doesnt shed scutes like my sliders and painteds.)The plastron surface has a dried out appearance in several spots. On the plus side, he still eats heartily. I am giving him reptomin, flukers, romaine lettuce, tomatoes and aquamax. On the technical side I am wondering if anyone has any technical suggestions for improvements on the treatment. I could post a couple of pictures of his shell if needed. I feel like an idiot for not catching this sooner.