freshwater beach sand for skinks?

Question
my fire skinks have a required RHL % so i have sphagnum moss in their enclosure.   im wondering if freshwater beach sand would be harmful in any way?  i plan on boiling and dechlorinizing the sand if i can use it safely, im unsure if they can become impacted like some other species?

i was entertaining the thought of adding a shallow retaining wall in one corner and giving them a landscape variety.

im unable to find a reliable resource pertaining to my question and as always any help or information would be incredibly appreciated!

Answer
Hi Jamie,
There is much controversy with using sand as a substrate for a skink..when I find this type of controversy, I tend to stay away from the item.  Yes, they can become impacted from the sand...
The fire skinks prefer to have a substrate such as coconut bark, or the sphagnum moss that they can burrow into easily. The do need the moderate humidity, and sand can be too drying and also too wet when moistened.
As I said, I tend to go with the safe way...just not worth the risk. Too many ppl say they have used sand for years, only to see them saying their skink(or other reptile) died "for no reason" without having a necropsy done..chances are it was a blockage, most likely due to sand. Also, beach sand is a pretty large grain, which makes it even worse.
If you want to give your skink different levels to climb and explore, that's great!!! Just make sure that he is able to get back and forth over it with mo problems, and of course make it safe so that it can't topple over on him.