Reducing spotting on the sand etc.

[atoll]

When I had Radions XR39s gen 3s I successfully made and fitted my own diffusers. I even sold them on eBay. Some months ago I upgraded to 2 x Orphek Atlantic's V4s onmy D-D 1500 pro reef. In order to reduce light spill my Orpheks are 10" off the waters surface. The slightly downside is I get some spotting on the sand esp red.
I have seen a DIY diffuser fitted to an Orphek compact but it was fitted 1.1/2" below the light. To my mind and experience this is to far away from the light source and would reduce PAR too much and even scatter the light.
too much.
I have a design of diffuser in mind that will fit close to the light, about 1/4" off the light. I am confident this will eliminate spotting on the sand. Any thoughts o the above.

 

[T-J]

Are you talking about the "disco ball effect"?
I guess the only way to really know would be to get a PAR and spectrum meter and test the diffuser on the Orphek that you don't think is good. Then test the one you're designing.

 

[atoll]

Are you talking about the "disco ball effect"?
I guess the only way to really know would be to get a PAR and spectrum meter and test the diffuser on the Orphek that you don't think is good. Then test the one you're designing.

U fortunately I don't know anybody with a PAR meter. However the manufacturers of the diffusers state there is a 11% reduction in PAR which isn't so bad in truth.