I love them for my night time lights, they are brighter than the "moonlights" that come on light fixtures, and they give that black light effect to my corals. So for a night time thing I love them, I got 2 over my 75g and 1 over my 36g. As far as day time I agree they are not all that great for a main light at least for that big of a tank. but them plus your main lights they do great so that extra poppy color in your tank.