Should I change my optics?

Okay, so I am totally new to LED's. I bought a RapidLED setup (prebuilt by someone else). I will be placing them on my new 90 SPS dominant tank. Heres a basic description of the setup:

48 Cree xp series 3 watt LEDs
Two 14"L x 6"W heatsinks - Each have 8 XP-E royal blue, XP-E 8 blue XP-G 4 neutral white, and 4 XP-G cool white LEDs.
80* optics on all.
Runs off 4 dimmable meanwell drivers
RapidLED daylight controller for dimming control and sunrise/sunset control

I hate doing things that I do not understand, but there are so many things going on with this new tank, that I just need to get these lights up and running so my corals stop losing color... What is limiting me right now is what height to mount them.

I was told to mount these fixtures, with 80 degree optics, about 14" above the surface. Would it be better (specifically for SPS) to switch the 80's out for 60 degree optics and mount it lower? My main concern is that I do not want to be restricted in placement for the sps. In my old tank (with t5's), the top of the rocks were completely filled, and some corals couldn't even be moved down from the frag rack. I do not want a repeat of that issue..

Can someone please recommend which is the better option here? And the reasons why? This will be greatly appreciated!!!

 

I see your logic in your thinking, but you've got a bit of misconception.

The depth of the tank is what really determines what optics you need. I'll assume you have a standard size 90g tank (48x18x24); being 24" deep 60deg optics might be a better fit for you.

However, if you change to 60deg optics, you will need to mount the fixtures FURTHER from the surface, not closer. Narrower optics and closer to the surface will create spotlighting galore. And this is the next factor in optic selection; any limitations on mounting the fixture. If the person who owned the fixture before you had a canopy, then this is quite likely why they selected 80deg optics. They would have had a limited distance they were able to mount the fixture away from the surface.

Lastly, the other component that factors into optic selection is what type of corals you have and where they are placed in the tank. If you want SPS all over, then narrower optics are for you. If all the high-light corals are in the upper half of the tank, wider optics are a better choice.

Depth of tank, desired (or limited) distance from the surface you wish to mount the fixture, and type/placement of corals; these are what really matter. Hearing your concerns/desires, as long as you can mount the fixture 16-20" away from the surface, I'd use 60deg optics.

 

Start with 80 and place your fixtures high for now. See how your corals respond. You don't want to hit them with high light right away. They will bleach. If you see you need more light later you can replace the optics. It's easy and it's not going to be a huge difference between 80 and 60 as these are ballpark numbers. Good luck!

 

Okay. I do have a canopy, so I think I'll stick with the 80 degree optics. How far do you guys recommend that I mount them (with the priority being the SPS)? I was thinking maybe 10 - 14"? Yes it is a standard 90g.

 

FWIW I removed my optics, all except the front where the water is the deepest. My rig is also a rapidLED DIY build and I have it mounted 14" above the tank in a canopy on a 65g mixed reef. I removed the optics because my sps were bleaching. this resolved the issue,at least so far...its taken a lot of reading and trial and error to get the lighting balanced but is totally worth it

 

8-10" in that case.

 

Thank you! Are there any good writeup's where I can learn more about leds? I hate doing things that I don't understand.. I feel that it always leads to trouble (not to mention wasted $$). Once things calm down with the new tank, I'd like to spend some time reading about leds.