?? About sand bed

[NJW]

I just added 1 inch of regular southdown play sand from home depot to my existing 2 1/2 inch deep bed of crushed coral. I have had the crushed coral substrate for about 8 monthes, and I was wondering that if the addition of the sand to the existing substrate will harm any of the bacterial colonies in the crushed coral, and if it will cause a massive die off of bacteria due to the deepening of the substrate.

[rshimek]

Hi NJW,

No, it will have just the opposite effect. The sand bed will provide a much larger amount of surface area for bacterial growth. Bacterial will grow down as far as you want to add sand...

You might wish to examine some of my other posts discussing sediment grain sizes and their effects on organisms in a sand bed filter, however. The crushed coral isn't a good idea. :D