Mounting Radion Fixrures

[Reef Frog]

What is the lowest recommendation for the distance between Radion fixtures and the surface of the water? I'm talking about the latest generation Radions.

I only have 6-8 inches of space from lens to water surface to work with. Is that enough? Will the light quality or performance be hindered in any way? This would be on a mixed stony reef, LPS predominate.

I see many photos of Radions mounted quite high -often several feet. What is the advantage to this, if any?

Thanks!

 

[Relativity]

8 inches because any air bubbles will spray about 7 inch out of the water mist

 

[Reef Frog]

Thanks. So it's OK in terms of salt creep.

But what about light quality. Since intensity is almost infinitely adjustable, I'm assuming that's not a concern either. Right or wrong?

But what about the even spread of light? Any danger of hot spots or dark spots? Disco effect? (I don't really know what that is) Do I need more fixtures over a 5 or 6 foot tank than normal? Any other reasons this is a bad idea?

I ask because I've never seen it done in photos. Is there a reason?

Hoping an Ecotech representative can chime in as well as a hobbyist who's done it. It will save you guys a phone call! Thanks.

 

[u4ick]

The main issue besides getting the thing too "wet" would be spread. Intensity can be adjusted to compensate for added par.
I would say if you can do 8 you'll be just fine, prob want to consider the wide angle lenses at that close or any closer for sure. Disco effect might be seen in reef up high....maybe. Tightly clustered LED's don't have this issue in the same way row style LED's do. To answer the Q on # of lights is about foot print of the tank and what direction is best to face the lights, so need more info there.
As an example I put four G2's on a 265 (84x24x30) I put the two center ones going front to back and put them as close to the braces as I could without casting any shadows. The other two I did side to side since both corners have overflows, plus the light easily does 24" wide footprint. It does very well this way with me at 8" off water.

To answer your other question about the advantage of high up off the water would be to get better spread, better color blending, and getting the light up higher in output without burning the corals.

Have a 325 cube (48x48x34) that is backed up to the wall. Have these at about 20" off water. Lights are never in my way like this. Did the front two side to side, and the side two front to back. I was wanting to light the front of the reef on all four sides, like a horseshoe. The middle gets plenty of light from this arrangement as well and doesn't leave me burning corals up at the top of the reef.