Powerheads placement question

[Fredrxn]

Sup guys...I have a waterbox reef 130.4 with 2 Nero's 3 running on random flow..there running at 50% power...is that enough flow.......ruturn pump is 1600 gph... I was thinking of putting a smaller powerhead in the back of the tank closer to the sand to get some flow around the rocks and on the sand.. because I am having cyanobacteria problems tank is 2 months old...here's a picture of placement of the Nero's 3 and videos of flow

 

[Bigred321]

I would be worried about the sand being blown around. My advice is to put a pump on each end. Yeah

 

[Fredrxn]

I would be worried about the sand being blown around. My advice is to put a pump on each end. Yeah

Ok

 

[Rp8]

A gyre mounted vertically on a back corner will keep it moving, that’s how I keep mine flowing detritus free