Is there anyone who has used Cree XR-E Royal Blue LEDs to supplement a 400w 20k MH? I'm thinking about adding them to my system to get more of the actinic look, but not sure how many LEDs I should get. I don't want them to get washed out by the 400w halide.

Thanks guys.

That will be a tough one just from a coverage standpoint. You will be able to get them to show up with the use of tight optics, but it kills your coverage. How big is the tank and the pendant?

Thanks for your input. It's a 30g tank (30" wide) with a custom made canopy. The halide is mounted 15" from water. Maybe I should just forget about using both of them simultaneously -- use the halide during the day, and switch to the Royal Blue LEDs in the evening for a few hours. Would 6 XR-E RB be bright enough to enjoy the actinic look? I just like to see my corals pop, something similar to Zook's system. ( There's a pic of LED only here http://www.nano-reef.com/featured/?tank=34 )

If the 20k doesn't make your coral pop I would suggest T5s. LEDs are nice I use one 3w LED for a night light but for ease of use I would just add few t5s. It is hard for me to believe you need more blue what kind of bulb are you running?

OK, thanks. T5s seem good too. I'm using XM. It has a good amount of blue and I'm happy with it, but thought it'd be more interesting to get the crazy colors of the actinic look. Is one 3w LED enough for your system as a night light?

i would just get T5s. unless u want to spend a little more up front then 50 LEDs =)

wow...400 watt on 30 gallons? pretty strong lighting and I doubt anything will affect that strong lighting but you can put a cycle on your lighting and run actinic lights from 9:00 am till 11:00 and then run the MH light from 11:00 till 4:00 pm and then back to the actinic.

But with that 20k light you're not going to see much growth in your coral like with 10K. A 20K is already very blue and poor for coral growth.

Actually, considering it's 400W, T12VHOs might be a better choice. URI or UVL Super Actinics would give you the pop you want.

OK, thanks guys for the helpful tips.

Or you could buy two 24" Reefbrite strips. But, that's realll pricey.

Reefbrites will have a really hard time being seen over a 400w MH.