The Kessil Magnetic Lenses we saw at Reefapalooa Orlando turned out not to be lenses at all, but rather a nifty add-on magnetic diffuser. These ‘Diffusion Opticals’ as Kessil calls them are made of a translucent glass encased in a soft rubbery material that is attached to the Kessil AP700 through built-in magnets.
The magnetic diffusers are of two kinds, there is a Major and a Slight version of the diffusion optical, each with varying degree of diffusion of the light coming from the Kessil AP700. Since we’ve never really had a swappable diffuser it’s hard to say which one is best for which kinds of tanks, each one will reduce hard shadows and reduce light intensity to some degree.
The need for these optical diffusers is relative but they serve to ‘soften’ the point source nature of the AP700’s LED clusters. The Major Diffusion Optical is probably best for shallower and broad tanks where you want to get even more light spread, softer shadows, and lessen the effect of shimmer lines if you have turbulent water surface. If you have a deeper tank, little surface agitation, or only want to soften the point source light a little bit, then the Slight Diffusion Optical is the one to consider.
But ultimately your use of either the Slight or Major Diffusion Optical will depend on your own tank size and depth, the kind of corals you keep, and your personal preference for the look of the light over your aquarium. The Slight and Major Diffusion Optical add-on diffusers are available in two-packs from Kessil for about $45 each, but there’s nothing to say you have to use just one type, or have them over both LED clusters of your AP700.