Possible to reduce sand bed from 3.5" to 2"?

[nickbuol]

I've had my 120 gallon with 40 gallon sump (obviously only about 20 gallons of water) FOWLR tank set up since late November of 2012.

I put in about 120 pounds of sand (mostly special grade aragonite plus some AragAlive fiji pink to get things started).

Anyway, the bottom of the tank has a single layer of 1/4" think eggcrate for supporting the live rock without putting pointy rock pieces right against the bottom glass.

I measured the depth of the bed and including the depth of the eggcrate since sand obviously is down inside the squares, I have a minimum of about 2.5" and some around 3.5" deep. There are some high spots that hit about 4" or a touch more.

So the more and more I look into this depth, the more nervous I am about it. I wasn't trying to have a DSB because I fear the potential need to swap it all out some day, even with decent top layer sand sifters and good siphoning water changes to try to get detritus.

I *MIGHT* want to go remote DSB at some point, but for now I think that I just want to get the sand bed depth down a little closer to the 2" range overall.

I am getting some nice air bubbles in the upper couple of inches of some of the sand bed, which people told me was good and pretty normal for about 4 months in.

So, is there a good way to reduce the depth in the DT so that if I want to do a DSB, I can do it remotely and take it "off-line" as need be for maintenance without having to scramble under the gun if something goes south in the DT?

Thanks a ton!

 

[Nano sapiens]

Stirring up an established SB that hasn't been regularly vacuumed always has the possibility of unwanted consequences, so proceed with caution.

Assuming that the SB is not a total mucky mess, then I'd remove small portions of the top 1-1/2 layer over the period of a few weeks to be on the safe side. The tank should adjust as you go along, but be aware that you may see some dino/cyano form on the SB and LR due to substances being released from the disturbed SB. Also, keep up a regular WC schedule, clean filters and change GAC regularly (if used) to help remove any stirred up undesirable substances.

Once you have a 'shallow' 2" SB, then it will require regular detritus removal via vacuuming to function efficiently. If not, over time it will lead to eutrophication of your system and, worst case scenrio, a system crash.

 

[nickbuol]

Thanks. The sand is pretty clean actually. I didn't even have fish in there until a couple of weeks ago, and I've vacuumed the top layer when doing water changes. I will just take it super slow.

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[tippmannsniper]

Suggestion.. Perhaps do it at the same time as a series of small-moderate water changes.? Use a larger siphon and go slow. Anything that is kicked up will largely be removed via suction. Can't imagine any issues then, especially being it is a younger system