Skimmate and filter socks changed color

[Tuffloud1]

So when cleaning my socks and changing out my skimmer cup, I noticed a drastic change in the color.

It has always been a medium/dark tea color and now it has turned very dark.

Any idea what can cause this to happen?

 

[lapin]

If you let them sit in water it is prob hydrogen sulfide.

 

[Cory]

If you let them sit in water it is prob hydrogen sulfide.

Yes this or more organics instead of sand dust.