Sand Bed Changing????

[aqua blue]

I am seeing an increase in hundreds of small bubbles just below the surface of my sand bed. A few of them are visible on top of the sand bed. The sand bed visible against the front glass of the tank is changing to a brown or dark orange color. The surface of the sand is slightly brown in color in some areas. I am also seeing many small bubbles rising to the surface of the water.
My water tests are:
pH -8.2 Ammonia - 0 Nitrite - 0 Nitrate - 10 Salinity - 1.024 Temp - 79
Is this a normal change for a sand bed or could this be a sign of a problem ahead?

 

[dubba-r]

The bubbles are a sign that your sand bed is working. Its converting your nitrates to I think nitrogen, which will float to the top of your tank and pop! But anyway, thats the benefit of a DSB

 

[aqua blue]

Thanks for the reply Dubba-R. Any others with comments???

 

[wrassecal]

Dubba is right and the brownish on the surface of sand is probably some diatoms and will go away on it's own. You will get lots of colors in the bed that you can see up against the glass and worms too! Sounds like your dsb is crankin up and starting to do it's job.