Black soot in my calcium reactor

[Zach117]

What does it mean if there is a really fine black soot that has settled in the body of my calcium reactor? I am not running any carbon currently so it is not that. My GFO runs after my reactor so I don't think it is that either. It is only in my reactor I don't see it any other place in my sump.

How do I know when the media is exhausted?

 

[Zach117]

bump

 

[akindbro4u]

what media are yo using? sound to me like undissolved solids. Arm media has a small amount or material that undissolved at a lower PH. if the as the other media is dissolved it will settle out. For you second question. i always change the media when i get below half of the full volume.