Personally I don't have any sand in my sump. I do have a bunch of live rock and rock rubble for bacteria colonization. I am a strong believer in macro algae like cheato in the sump to consume nitrates with a cheap CFL lamp. Also, I only have 2 sections in my sump. the large first section houses my Skimmer, reactor pump, cheato and finally the rocks. Then there is my return section. The rocks prevent cheato from getting into the return section by creating a rock wall right to the surface of the sump water.
Good luck
Personally I don't have any sand in my sump. I do have a bunch of live rock and rock rubble for bacteria colonization. I am a strong believer in macro algae like cheato in the sump to consume nitrates with a cheap CFL lamp. Also, I only have 2 sections in my sump. the large first section houses my Skimmer, reactor pump, cheato and finally the rocks. Then there is my return section. The rocks prevent cheato from getting into the return section by creating a rock wall right to the surface of the sump water.
Good luck