Bottom layer of sand turning grey

[StrangeDejavu]

My tank is about 1.5 months old. I was working in my sump, preparing for a water change when I looked up at the bottom of my DT to see this. Is this normal maturing of a sandbed or am I getting hydrogen sulfide already? I only have 1.5 inches of sand. When I set the tank up, I placed the base rock in first and added the sand second, packing it in around the rock. Strangely enough, the light spots are where my rock is sitting. I have no CUC aside from 2 Scarlet Leg Hermits, which I have to feed myself since the tank is so clean. And yes, that's eggcrate. I plan on having a Watchman Goby in the future so I wanted to protect myself from shifting rock. Any help would be appreciated.

 

[GMay]

This normal. Until you have things in the tank that turnover the substrate you may have areas that have a different microbial populations, and this may be reflected in the color of the substrate. At 1.5 inches it is not likely to be completely anaerobic but may be of lower oxygen tension. This is nothing to be concerned with. When you get black and orange, then you may have anaerobic pockets, but even them they are fine unless you disturb them.

Happy Reefing!

 

[StrangeDejavu]

Awesome, thank you!

 

[Sk8r]

Get some nassarius snails or a fighting conch and they will stir that depth for you, eating the detritus down there.