Pet stores are notorious for dehydrated, improperly cared for, stressed out snakes so don't try to imitate the set up or expect a well cared for snake to act the way it did in the pet store. Most ball pythons will not soak unless there is something bothering them. I would recommend you put the water dish on the cool side or in between - you don't want to have warm water as that will build up harmful bacteria your snakes will drink.
Perhaps instead of all the questions you can post a picture of your set up and we can go from there with suggestions. There are a lot of knowledgeable, helpful people on this forum - but they do have a low tolerance for people that ask a bunch of questions that should have been researched and answered before the purchase.
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Tosha
JET Pythons
