My red eared slider has a swollen eye and some shell rot.....?

I recued 2 year old clyde abt 2 mnts ago from 10gals of algea filled water. even he was growing mass amounts on his shell. i cleaned him off and set him up in my 55gal with his old tank on top as a basking area. it is easily accessable to him. the water is 74-80* and his basking spot 85-90*. he is eating normal and begs constant. he is very active in the water, but refuses to bask. i thot he would jus need time to ajust. but just yesterday, i got worried and started trapping him in his basking area. he freaked as normal but i made him stay 15 twice. today i went to do the same, but first i cleaned him with a soft toothbrush, the put turle wax on his shell and head.... i gave him 15 min but then took him out to hold or let wonder around (he is calmer than in the basking area) tryin to aquire more dry time. i then noticed the scales on his belly where red. i googled and found to put poroxide on the infected parts nd keep dry. so i did and put him back in the basking tank without the light, i didnt wanna fry him