Be sure you have a good UVB lamp, and a hot basking spot. UVB for two turtles should be strong, I'd recommend a reptisun 10.0 UVB. I keep my turtles in a 90 gallon tank (they are 4 inches each). Be sure to have a good filter.
For food, calm down on the tomatoes as they have an acid in it that isn't too good for turtles if you're feeding daily, also it's a fruit and turtles should have fruit about once a month (as treats). Be sure to feed them greens daily (green leaf lettuce, dandelion leaves, turnip leaves). No iceberg lettuce as there is no nutrition in that. You could give them live guppies, minnows, apple snails..and crickets and mealworms once in a while. Also once or twice a week: carrots, kale, green beans, squash, etc.
You could check on here for more about diet.
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