[TheOldSalt]

Deeper is not better.
It is popular, but not better by a longshot.

Denitrification only occurs in the top 1.5 or so inches of the sand bed. Deeper than that, and instead you get reduction. As the toxins produced by this work their way back up into the top layer again, they are again nitrified and then denitrified, but not all of them are. Some work their way back down again to start all over, and some escape back into the water column.

This is grossly inefficient, and while not particularly dangerous unless something stirs up the deep sand bed, it's still inherently less safe.

Deep sand beds--> cost more, work less effectively, take up volume in the tank, and are risky.

Shallow beds with plenum--> Cost less, take up less volume, pose no risk, are vastly more efficient.

LOSE THE ANEMONES. They do not belong in a new tank, nor in the tank of a beginner. They are practically immortal in the open sea, but they generally don't last a year in the aquarium unless kept under exemplary conditions. they are slow to reroduce, and their numbers are being seriously depleted in the wild due to overcollecting. Don't become part of the problem which could lead to them becoming illegal to import. If we don't regulate ourselves, somebody else will do it for us, and we won't like it when that happens.