I have 3 sliders, one is about a year and a half and the other two are under a year old. They NEVER have had a problem eating, they would eat all day if I let them. Recently, my petstore stopped selling the filter cartridges I need for my filter, so it has been a while since I replaced it. I got up to feed the turtles this morning and they did not touch the food. I totally cleaned the whole tank today and bought a brand new filter. But while I was cleaning the tank, I had the turtles in the sink. When I came to check on them, I saw small pieces of rocks in the sink. I'm assuming they ate rocks from the bottom, but the rocks I have in the tank are almost quarter size. These pieces look like small pieces that must have chipped off. I left them alone after I cleaned the tank and they seem to be back to normal, but they still wont even look at the food. The old turtle halfway snapped at the food and took a small bite, but then just swam away. What do I do??

