I dont know Gary, I doubt that even with MH's our sand is getting the light equivilent of a shallow lagoon. And as skimmed clean as we keep them It just doesnt scream turbid to me.
Id like to know at my tanks depth of 24" and my XM's what that coralates to in depth of natural ocean conditions. I have no idea, maybe im wrong and my sand is getting the same as would be found in shallow water. Whats the depth of a lagoon 2'-5'?
If I had to quess and thats just what im doing, Id bet my tank is more like 20'-30' depth. Again I could be way wrong.