MH Bulb change

I am going from 20k to 14K. Do I change one bulb and not other? Change both and just leave them on less?
Also I have been used to the blue color of the 20k so it will take some getting use to the brighter color 14K light, but Its growing on me and I think it will help my coral grow better.
Also I my timers are set for my MH to go off at 10:30pm and leave my Actanics on for another hour then moon lights come one. 6am my actanics come back on and then at 4pm my MH come on with my actanics still on. Does this sound ok or should I change it a little with the new added par?
Just a heads up I replaced them both and also had the MH on longer yesterday longer then 10 hours do to get them Saturday and wanting to check pars. I also replace my GFO with Kent marine Carbon and when I checked on my tank this morning I was shocked to see two of my Frags faded and two of my button polyps looking rather withered or faded. I quickly contacted someone that could help me and think I get things under control.
I took out Carbon, because there was a recall on some date of it. Mine was not included in this, but I will not use Kent Marine Carbon again. I put in Chemi pure and it has never done me wrong.
I put the two frags I could move into my frag tank and I think they will be ok, just a little bleached. I am going to leave my one 20k on my left side and 14k on right side on for 2 hours today and then off until tomorrow. and only have them on for 4 hours at time for a few days.
This sound good?
I am pretty sure it was lighting with some help from another member  and that's why I am  asking so many questions about it.
Thanks John very much for your time today.I owe him one.
This is what I am dealing with as far as Lighting. lol

 

When changing out any of your MH bulbs your going to want to reduce your lighting cycle, id say gradually raise it back to a normal schedule over a month or so.

 

So change one at a time and reduce light cycle? That's sounds like a plain I made with another member and I just want to get some other exsperiances out there too.
hope to hear more out of others.

 

I always changed my MH bulbs at the same time....reduced time on. You could also use layers of screen (window screen) instead of reducing the time on...just slowly remove the screen, layer by layer, over the course of several weeks. Another option is to place the corals on the sandbed and slowly move them up over the course of several weeks. Nice open aquascaping!! :=0)

 

Ok after scouring the internet and asking a lot of question I am going with 4 hours on with both bulbs changed from the 20k to the 14k. This is half of what I normally have them on for. I am going with this cycle:
I am leaving my Actanics on as normal from 6am to 10:30pm and have my new MH bulbs come on at 4:00pm and go tell 8:00pm then my Actanics will stay on until my moon light turn on at 10:00pm and stay on tell 6:00am.
I think this will work well. I think corals are doing ok, but I see that my fish also know that the light is a lot brighter to I think too.

I am thinking of doing the door screen thing, but can't find the best way to put it just under my lights. I will keep thinking about it.

Anyone think I am going about this wrong or does this sound good?

Thanks everyone not sure i really wanted to change my light bulbs not, but it had to be done. I should have just stayed with 20k. Live and learn I guess.

Kyle