In addition to unscented you should not use "splashless" bleach either. It's also more difficult to rinse out thoroughly. Plain old cheap bleach FTW!BTW...forget to mention. Always use unscented bleach as the scented bleach products can have some funky detergents in them. I nuked several tangs one year unknowingly cleaning filter socks with scented bleach. Despite two rinse cycles in the washer...it wasn’t enough to get it out.
I’ve also seen this happen when people rinse sand. I always try to buy the cheapest unscented bleach I can find. It’s less likely to have detergent in it.