Depth of Gravel in Tank?

too much can cause anaerobic areas, as well as make it much harder to keep clean. 2" should be fine. what type of fish do you have?
 
In unplanted tanks, I use about an inch. That is easiest for me to take care of by routine full-depth vacuuming.

In planted tanks I use 3" or more, depending on the height of the tank.
 
yea mines a 20 gal i have probly 1 1/2-2'' and my plecos pull a plant up a night usually
 
i have about a 2" gravel bed in my 55 gallon tank.
 
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