if you are concerned about soft shell, then you MUST get your turtle some sunlight! sunlight causes a chemical reaction that produces vitamin d in the body. vitamin d is necessary for calcium absorption. if your turtle doesn not absorb calcium, it gets soft shell. if you are noticing white patches, that sounds fungal--better get to a vet. direct unfiltered sunlight is best, but you must also provide shade so your turtle can regulate its temp. also, glass filters out the necessary wavelengths, so tkae them out of the aquarium! besides an aquarium in sunlight would bake your turtle, think of those poor ants on the sidewalk under the magnifying glass. another thing that is necessary is a uvb FLOURESCENT tube, NOT A BULB think flourescent, more specifically, think zoo med reptisun 5.0. this is the best one. they are pricey, but as luck would ahve it, they are on special right now at LLL reptile online, go get as many as you can afford. also, lettuce is NOT good to feed, its very nutritionally lacking. feed mustard, collard, dandelion (pesitcide free!!)squash, cantaloupe, green beans, peas, green peppers, yucca root, carrot, etc. try to feed a few each day and change what you feed often. if you would like more info you can check out melissa kaplans web site. she has great info on most reptiles.
meagan