Swamp brown water

[SkillKing21]

For the past few days I have been having this really creepy dark brown coloration to the water.I can't even see the back of the fish tank due to it.The fish don't really seem to be bothered at all.I checked Ammonia salinity nitrate etc everything was good.Anyone know why this is happening or how I can make it go away?

Current tank, 200 Gallon Bow Front,FoxFace,HippoTang,YellowEyeKoleTang.

 

[BigHildy53]

Have you changed carbon or GFO, without rinsing first?

 

[SkillKing21]

I have change the carbon out every 1 week.

 

[SkillKing21]

I also do rinse the carbon.