Sand Verboten
Reed, I think you're courting disaster with using coarse builders sand for substrate. It might be good for desert snakes such as rattlesnakes, but not for corns.
[1] Too rough and "alien" to the natural habitat that corns would seek, which is more like that of a temperate forest or savannah floor. "Alien" = stress. I think this would also be true for your kingsnake, though they are much tougher snakes in general.
[2] Too dessicating--it will contribute to dehydration of your snake over 2 or 3 months, too slow to be obvious at first. How do I know? Been there, done that with Calci-Sand, and the dessicating properties of coarse builders sand are similar.
[3] Still small enough to impact from what I've seen of this. Corns will swallow sand in their homes even if you feed separately, and will also get it in their vents [cloacas].
When I started, I asked if I could use Calci-Sand since "it looked cool". I didn't know anything back then--being a people MD didn't mean I knew what I was doing with snakes without further training. I was told, "Well, we recommend aspen, but you 'can' use Calci-Sand if you want." WRONG! My corn Valentine nearly died due to impaction and dehydration from sand, not eating for 2.5 months as a hatchling, except that a brilliant vet friend of mine saved her.
Way too many tell beginners [me just 18 months ago] that they should do something, but that they can do another if they like, even if the "another" is harmful. I disagree with this. I want strict rules until I really understand the physiology and environmental ecology of animals and their habitat. Once you have a deeper understanding that comes with wide reading and longer experience, you can safely try slight variants while observing carefully.
Listen to the experience on this forum. Use aspen chips or plain white [no chemicals, no dyes, no scents] paper towel only.
See my link above for an internet source for aspen. Very cheap, you'll be glad you did it.
'As-pen' as much money as I need to care for my corns,
Doctor Mike