My Dry Rock and sand is turning brown

[rickyst1]

New set-up Rookie here,
Firsted added dry sand, 40 #dry rock , RO/DI, salt 3 weeks ago to my 65.
Added 10# of live rock almost 2 weeks ago and just noticed the pristine white sand and rock is turning brown.....is this the normal process? Will it stay that way?

 

[hackteck]

yes its diatoms they live off silicates after all the silicates are used up they burn off give it a few weeks

 

[DA fisherman]

yes its diatoms they live off silicates after all the silicates are used up they burn off give it a few weeks

+1
Some would say it's the beginning of the End to your cycle.