black crud on my sand!

[i like fish]

can anyone help me here, i did a fishless cycle with shrimp..and now i have black dust like crud all over my sand in my tank, i can stir it up and it jsut settles back down on the sand, i did water tests today

nitrite - 0

nitrate - 80 ppm

ph - 8.2

ammonia - 0

i dont have any clue what this stuff is, but it wont go away, its been there for at least 2 weeks, since the shrimp has decomposed completely, there were prolyl three of the shirmp, fairly big,

any help or ideas would be greatly appreciated...thanks all

 

[scuba_steve]

id suck it out

 

[seaham358]

The Nitrate is real high, you planning on a water change to lower that? If so do what SS says just suck it out. Do you have LR? Could be some die off from the LR. Without a pic its hard to say.