That's very small sand, it move easyly with the powerhead.
What about if I put the powerhead the most at bottom and the middle of the side glass aiming the rear glass pointing on top... Hmmm sorry I have bad english and it's hard to tell what I mean, so here another paint picture:
I mean the fan is on the middle of the wall but the lower possible near sand, and propelling the water on the rear glass toward up direction... Do you understand what I mean or it's too unclear ?
I know it would be great to have dual 300 gph
, but I can't have a refund for my koralia pump... I didn't keep the box and the manuals...