Just Got 2 Red Ear Sliders 4 Days Ago And They Wont Eat?

Sept 27 They where picked up. would not eat tried Nutrafin Basic Floating Turtle Gammarus Pellets (came with turtles) fyi they are both about 1 1/2 inches. picked up Reptotreat gammarus natural shrimp on sept 28th one of them ate 2 shrimp other one wouldn't eat. sept 29th neither would eat. still neither eat. they are in a 10 gallon tank (recommended by store) there is no heater in the water atm but the water is staying at 78degrees i have a thin layer of the blue and white gravel u can get at any pet store (they are large enough i believe) then on the right side i mounded it higher sloped up so they can climb outta the water also have a larger rock for them to bask on. use a 60watt bulb atm from a flexible lamp. pointing down on to them. i used distilled water to fill the tank (poland spring) i rinsed the rocks off very well (water still got abit foggy a little white stuff on top of the water im worried about) i read that u are suppose to feed them one at a time in water but out side there tank. so i been putting them in a dish with a high rim filling it with (poland spring) at room temp 75-80degrees put a few pellets and shrimp in. please i am very worried about them have any ideas? i also believe they are males but it might still be to early to tell if that makes a difference.