AL1;909829 wrote: To be honest I didn't notice any major difference in growth rates, only change noticed was the actual light spread but thats a given when adding the optics. I actually had the left side of the tank without optics for about 3 months and the right side with 90s, sps on both sides and all are doing good. I can't really say I've noticed any significant difference. I have red dragon, bonsai, strawberry shortcake, tri color valida and whole bunch more and they all do great. I went ahead and added the optics to the 2nd unit more so they can look/be the same they've all continued to do well. I know there is a lot of negative or bias opinion towards the mm units but in my opinion those are people trying to justify the expense. You can convince urself to see things the mind is a beautiful thing. Without a true scientific experiment throughout months of research and careful measurements no variables i think it's not fair to say the mm don't work. If ur ever in my area give me a shout and come see for urself. There are so many other factors that go into play regarding growth it makes very difficult to say a certain led is better than another. That's just my $.2, I know most will disagree but I'm speaking from my experience with the mm. Then again I've never had a "high end" led unit and probably never will. If growth is what u want then MH is the way to go. There are some hybrid units out that incorporate mh and led so u won't have to sacrifice the color pop. I myself am heading in that direction, reef brite has a super nice hybrid fixture that will soon light up my reef.