Water movement under rocks...achieved.

[Sk8r]

I build arches above the sand, putting 'pillar rocks' lowestk and setting arched rocls above them, so that my rockwork is fairly open, though massive.

One prioblem remains which I think is a sneaky and common one: even if you have fairly decent subsand critters: Gunk under the rocks

Haven't had a functioning Gyre or other water movement in there for a whild. I ggt a new Gyre recently, installed it, and the water moved, for sure. Thy fish were a little addled at first. But outside of a really nice (for one's size) skimmer, I'm convinced positioning the various water movement devices to sweep under the rock is a good thing. Gyres do it by the nature of what they do, but others can be aimed to do it, and I think it a gpod thing tp have that crud move on to the sump. The water looks brilliantly clear this morning.

 

[Axel33]

why do you need so much water movement? do you have SPS?
I have a bunch of sand in my tank and my lower lvl is not getting much movement. But I see sometimes stuff that might grow into alges and I use a turkey bster and turn over the sand.
I also have brissle warms, nassaris snails and a blue spotted goby but still need to do the turkey baster like every 5 day's.

 

[jeremy007]

More surface area for the rock as well with bacteria