I'm pretty sure that those are tannins coming from the media. My water doesn't come out crystal clear for most of my plants unless I've flushed the soil recently.Originally Posted by J-Rod
Would you happen to have any pictures? I have seen some things (black leaves, weird growth) from my semi-dormant plants each year around November. It could be a number of different things, so it would be helpful to see what the plants look like.
I hope you figure out what's happening with them and that they have a wonderful growing season.