Too much light?

[levichar]

I just purchased a MH/VHO combo setup used. ( http://www.hamiltontechnology.com/shop/?shop=1&cat=4& ..the bottom one) It comes with two 250w MH bulbs and two 110w VHO. That's 720w in a 75 gallon tank or ~9.6 w/g

Right now I have a variety of leathers (toadstool, rasta), kenya forest, orange digitata, cabbage, pink zoos, candy canes, xenias.
They are under four 110w VHO bulbs that are on for about 9 hrs/day.

Couple of questions...
1. Is this too much light? Am I going to fry everything?
2. Since I'm jumping up in lighting, any recommendations on the schedule?
3. How high should the fixture hang above the water?

Any advice is appreciated. I just want to make sure I don't vaporize everything in the tank.

 

[acer]

Depends on the type of bulbs= I assume your planning on using actinics for the VHO's. Then if you use something other than a 10K for the 250 watt MH's you might be OK - I would monitor temp carefully. Maybe 12K or 15k bulbs - depends on brands as the actual "color" spectrum varies. The lower Kelvin bulbs cuase great growth, but can "burn"/"fry" softies as they penetrate deeper and are "brighter". For the softies you have I would run the actinics alittle before, during and some after the MH's- depending on how you want the tank to look as they are pretty much for showing off color only. I would experiment with time periods for the MH's as heat will build-up and $$$ are spend the longer you have the MH's going. Start with the halides only a few hours per day so the softies get used to the brighter lights gradually. That way you can judge how they are reacting and put the lights higher over the surface or the corals deeper. WHY did you buy the new lights as the 4 x 110 watt VHO's are/is perfect for the types of corals you have now. Are you planning on getting other types of corals= LPS,SPS . IF yes, then have them toward the top of the tank and put the softies on the bottom and if you can keep the temp under control then you could be OK. Watch out for overcrowding as the corals will grow quickly with that type of lighting ( assuming other parameters are as good). I would come to the next club (PMAS) meeting - it is a big one so several "experts" = lots of experience will be there who are happy to help.

I just has to move a softy lower in my 90 tank that only has 4 x 110 VHO's due to recent changing to new bulbs and switched one of the bulbs from a 50/50 to a 10K. One of the larger softies that was toward the top of the tank had grown alot since my last bulb switch and I noticed immedietely after the new bulbs were put in there were no polyps extending anymore. I had to move a bunch of rock around to get him deeper in the tank and within a few hours the polyps began extending out again. So- you never know ......

 

[Steven Pro]

It seems to me that given what you have and the size of the tank, a lighting upgrade was unnecessary. Why did you change them?

 

[levichar]

I started out with two vho bulbs and 2 pc bulbs and wasn't very happy. The coral was happy, but I wasn't seeing any growth like I do in my 150 display tank (it has 4 vho bulbs) I bought a 2nd set of VHO bulbs and then the next day I had the opportunity to get a used MH/VHO combo setup. It was a good deal that I didn't want to pass up.

So I really had vho/pc until a week ago when I switched to full vho. The MH/VHO combo setup should arrive today.

I have a 150g running 4 vhos. I thought this 75g would be a frag tank with the MH/VHO combo. And I have another 75g FOWLR tank that I thought I might eventually use the VHO bulbs on down the road.

 

[vinstr]

I have a 90g with the Hamilton Tech MH/VHO combo hood, except I have 2 175w MHs instead of your 250s (I do have the same dual 110w VHO's). I have 10k bulbs for the MH;s and actinics for the VHO's and my corals love it and grow very well. I have to watch the temp of the tank as during the summer it can get too hot...
So, with a 75 gallon that might be too much and too hot...you can raise the lights up to lessen the impact (I have mine raised about 7-8 inches above the tank as well, so you might need to go even higher)...but then you would be wasting alot of electricity
Or lower the photoperiod- I have my MH;s on about 9 hrs a day and the VHOs about 12 hrs/day...

 

[zzpw3x]

Here are words that I have never said:

"I have too much light."

250W MH over 29 gallons.

 

[no hater clubs]

i run at lease 10w/g,in my 40g frag tank i have the same light set up as you do.250w20k mh and actinic vho.just make sure there's alot of top current so the light does not beat down on the corals all day long also i would add at lease two 4"fans to keep the heat off the top.also keep the light atlease 6"-7" off the top.there's no such thing as too much light,as much light as you have it does not compare to the amount of light the wild reef gets from the sun.good luck