Personally, I bought a bag of washed play sand years ago that I used in a lot of mixes for Mexican butterworts, all of which have grown well in it. But I also see people on forums often warning against it.
Any ideas on where the discrepancy comes from? Is it the size of the grains that people worry about or the fact that it may contain minerals? And when you warn people against using it, is that from personal experience of more of a general wisdom thing? Let’s get to the bottom of this!