An observation about sand and fine sand

[Reef Pilot]

Well, for me it is pretty simple:
Goby = no algae on sand
No Goby = algae on sand

And my P04 is consistently zero or near zero (Hanna checker). But yes, am sure sand traps P04. That's what the Goby is for. He stirs it up and it is taken away by the water column. Like I said, that is the easiest solution (instead of changing or frequently vacuuming your sand).