6 year old 75 Gallon

[Galvan]

Have had my tank for about 6 years now with animals and coral about 90# LR. Have about 3 inch sand bed and notice under my rock or between the rock the sand very brownish. Would it be safe for me to move my sand around or vacuum my sand when doing water changes? Appreciate your thoughts.

 

[Anonymous]

Vacuum the top layer only and then replace with some new sand. You can stir very small sections of a sand bed to get the locked up nutrients out.