My RES started showing some small whitish patches on their shells a few weeks ago, and I was wondering if anyone could point me toward a diagnosis. I strongly suspect it's a fungus but thought I should get some input from other keepers. Since I discovered the problem I've been taking them out for natural sun about 1 hour each day. I also changed the filter and did a complete disinfection of their habitat about a week ago - sprayed everything down, scrubbed with white vinegar, sprayed again, let dry completely. Didn't seem to have much of an effect. Water temp averages about 80 degrees, and as far as I can tell, both RES seem to bask plenty.
I've heard good things about silver sulfadiazine cream. Would that be the next step? Should I separate the turtles before things get any worse? Maybe dry-dock them? They've shown some signs of getting ready to shed, and I think it would do them good, but it seems to be going very slowly.

