Never had this issue. I have gone down as low as 320 grit. But it takes a lot more glass to achieve the desired results. As far as the medium, I've only used virgin glass beads. Some baits I've used half salt and half glass. Those were mostly senkos. Now I hardly use anything. I like being able to see the glitter in the baits. And colors are better too. I only weigh some senkos, and a wacky worm bait. I typically fish my wacky worm weightless, unless the water is over10'. Then I'll use a weighted wacky hook. My 5" wacky worms weigh almost as much as my weighted senkos. I've even been toying with the idea of using tungsten powder.