Ok ..finally went ahead and purchased the 21" Hidden Led - was concerned on how to mount on my Eclipse 3 Hood - was actually pretty simple. Removed the entire light fixture, leaving just the hood, attached the Hidden Led to the back rim and ran the wire through the cutouts in the back ....attach the suction cup-switch to the side and voila! LED is brighter than the fluorescent ..and the "shimmer"action gives the tank a realistic feel. The blue 'nighttime' setting is a lil dark for my taste but can live with it. All and all, pretty happy with the purchase! Will keep ya posted ..but good job so far Marineland!