I think this is a right thing to do, gecko's do not live on directly soft sand. They live on hard sand more like stone. The sand that they ingest is less then when living on soft sand. If they ingest that they get a larger amount that can be fatal. Mostly beginners will put their loves on soft...
I am sorry that i am putting this up again, but my leo (enigma) did something that is not normal in my eyes. She opened her mouth a couple of times rely wide and shook it like she did not want to but just happened. If we can find a way that they can process Thiamine, how can we give it to them...