So I've had this dark grey/black spot underneath my sand bed for a while now. It's about the size of a half dollar and doesn't seem to be getting any bigger or smaller. I've done a little poking about the internet and there seems to be mixed reviews on what it is and what ought to be done about it.
It isn't the sand itself because I can see between some of the bigger grains and it's definitely between them. Some kind of bacterial growth?
What are your opinions on what ought to be done about it?
It isn't the sand itself because I can see between some of the bigger grains and it's definitely between them. Some kind of bacterial growth?
What are your opinions on what ought to be done about it?
