need help for sand!!!

[ClOwNy_LoVeR]

hi bros i decided that my tank could handle my plan.i am currently keeping sps so i dug my sand and placed a full piece of prwan in the DSB in my sump.i placed it along the glass of the sump so i can monitor what's going on.but since,the sand has slowy started to turn black and have bubbles in it.i thought it would be effective as i started my sulphur denitrater with that and so far no problems/.btw the corals are al very healthy and good:)so it the black sand ok?thanks:)

[reeftask]

black sand means something rotten dead there. No water circulation. Bacteria start to grow but no idea how effective

[ClOwNy_LoVeR]

yup i put the prawn under.but the upper layer of sand dont hve

[reeftask]

yup i put the prawn under.but the upper layer of sand dont hve

of course.