sand depth calc

[nitrous]

how does the sand depth calc work bc i think the calc is broken here the tank is 24 long and 12 deep 20 gal and i think id like about maybe 1 1.5 at most 2 inches of sand to keep plants down
also i used this sand before and how come it looks kinda dirty and blackish on the top layer?

 

[Zagz]

Have you stirred the sand recently? When sand turns black it has gas pockets in it. You should stir it. Calculators are temporarily down for right now. I found that out last night. I have between 2-3" of sand in my tank. Of course my cichlids keep changing that around for me.

 

[nitrous]

ya my kenyi is not the easiest to keep plants with