Lighting time on advice

[Vitaminz]

If you are already running a 20k MH, I would suggest sticking with it, it is what your corals and fish are use to. I personally like the 20k better, more blue in it. Just remember when switching the bulb to reduce your lighting period with the MH to get your corals use to the new bulb. When I replaced my bulb, I went down to a 4 hours on for 2 days, then 6 hours for 3 days, then back to the regular 8 hours after that. Even then, I had a few heads of my corals bleach a tiny bit. Just my 2 cents worth.

Jeff