DSB and live rock stands

[Sean Smith]

interesting visit to a marine centre that has been in business for 20 years. The owner told me two things that I am now chewing over. He said:

DSB's take months to build gradually up - and I should be aiming for a depth of 6 inches.

Also, that my live rock should sit on top of stands to lift them off the sand bed.

I was planning to have a sand bed of around 3 inches - put all in at once, when I set the tank up; and to put the live rock on top of the sand.

any thoughts?

[phistio]

actually...i have my LR on stands that sit 1/4" above my sand...i prefer it that way...

[Irisservice]

First off 3" Sand bed is not a DSB 4" or more is considered a DSB.
As far as lifting the live rock off the sand bed it is a good idea but difficult to do. What i did was lay the rock out to have the least contact with the sand. I looks like caves along the sand bed.Hope this helps you
John

[BigE]

When the LFS guy said it takes months for the sand bed to build up I'd assume he means it takes that long for it to mature and become full of life. If he meant that you should slowly add sand to the bed over a few months you would constatly be moving your live rock to keep it above the sand bed as it becomes burried from the new sand.

[Todd Nicholson]

The way I kept my live rock off the sand bed was to bury tuffa rock in the sand so about an inch of it or less was above the top of the sand. Then placed the live rock on top of the tuffa rock.

-Todd

[HoopsGuru]

I think the guy you talked to was correct, but had your particular scenario mixed up with changing a sandbed to a deep sand bed. In that case, you do have to add it slowly to avoid destroying the aerobic bacteria bed.

In your case, add it all at once. Keep in mind that if you only go 3" it is not deep enough to create the anaerobic zone on the bottom to consume nitrates...the whole purpose of a DSB. If you don't want to add 4" or more, just add 1" and enjoy the extra room....you will just have to find another means of nitrate export whether it be by reducing organics with 1 or more skimmers, or doing more water changes. The 3" sandbed will do nothing more than the 1" except take up 2" of space!

Instead of platforms, I would just add your base rock and then pour the DSB around it. This wont decrease the efficiency of a DSB by much, there is multiple times over in surface area to handle your tanks bioload, not to mention the rock will perform a fair amount of nitrifying and denitrifying on its own! This is a good excuse to buy cheap base rock too!