After a long time wanting to try these I broke down and bought one. Tank is 4 x 2 x 2 currently with two 4 ft rows of neutral white (12 per row), two of the same in royal blue, and a two clusters of 12 royal/blue/violet in between. I hung the kessil over one half of the tank and if pleased was going to buy a second for the other side. On a 24" x 24" x 24" area it came no where near my crees. I wasn't impressed with the coral colors, but more so, the coverage just wasn't there. The corners of the 24" x 24" area were dark, and major shading. The first thing I thought was it looked like using a flashlight. Directly under the kessil was ok, but outside an immediate radius the output dropped off dramatically. My current DIY is similar to a T5 bulb where I have my LEDs from end to end of the tank, and the four rows spread out front to back. The tank is lit corner to corner. The kessil is going back. I won't say it's a bad light, I love the small form factor, but I don't like this "point source". IMO, I'd have to run 4 for corner to corner coverage and I'm not willing to spend $1600. The other thing that bothered me and the reason I had been waiting on trying these is that they don't fade to zero. There is an abrupt cut off. You may or may not care, I'm picky, but my DIY crees are pwm controlled so I get smooth sunrise and sunset. I had conceded to supplement two kessils to pick up fading before and after and maintain what I'm accustom to if necessary, but was only willing to lay out the cash for two. Just my experience.