I have two young turtles - about 2 inches and about 4 inches diameter - that I put in a new habitat (40 gallon long with ramps to a sand/dirt box, UV light, heat lamps over the 'beach', rocks on the bottom, external cannister filter). They have pretty much dug into the sand and not come out and I am worried about them! Is this okay? Should I remove the sand box? Not sure what to think. Thanks for any advice ... - Andrea