Is there a such thing as too much light?

[shanealanbeaty]

I wanted to see everyones thoughts about reef metal halide lighting. Like is there a such thing as too much light? How long does everyone run their lights for? My goal is to eventually have a thriving sps dominated tank. I just currently switched over to a 58 gallon tank L 36.5 x W 18.5 x H 21 from a 55 gallon. I am currently running two 250 watt hqi metal halide lights. What concerns me is now that my tank is a foot shorter, obviously my bulbs are place a lot closer together as well. Lighting from the closer placed together bulbs will now overlap in the middle much more than before. I was running them 8 hours a day on the 55. I had great growth on my acropora, but my digitata seems to be growing very slow. This is my first attempt at sps as well, so this is all new to me. Does digitata need/want less light than acroporas and need to be placed lower in the tank? I was concerned that I might be providing too much light and/or too long of light exposure. Thanks again everyone on this site. You have been more than helpful.

 

[ReefWreak]

Yes. I run my lights for 7 to 10 hours, depending on what I feel like running based on electricity usage, outdoor temperatures, indoor temperatures, etc. You won't have a problem with too much light if your tank was the same depth before even with the overlap. Acropora like light much more than montipora. Montipora are generalized as being from deeper waters or shadier areas, so they tend to do better with less light than acropora.

If growth is slow check your calcium and alkalinity with decent test kits (API are cheap and accurate and easily available).

 

[ReefWreak]

Yes. I run my lights for 7 to 10 hours, depending on what I feel like running based on electricity usage, outdoor temperatures, indoor temperatures, etc. You won't have a problem with too much light if your tank was the same depth before even with the overlap. Acropora like light much more than montipora. Montipora are generalized as being from deeper waters or shadier areas, so they tend to do better with less light than acropora.

If growth is slow check your calcium and alkalinity with decent test kits (API are cheap and accurate and easily available).

 

[poolkeeper1]

I only run my MH for 6hr a day together with my T5's for around 10-11 hrs on the sunrise/sunset program from Neptune, My halides are staggered on and off also at 30min apart each. Hope this helps, If I run any more that this I see Algae problems start.
3x250mh 4x80wT5

 

[zef004]

I'm with bill about the time table. Are you running t5 or VHO? My lighting is 3x250 HQI with 8x36 t5 about 12-9in from the waterline. MH are on for only 5 hr and 15min apart and T5 10hrs And the sun hits the tank for 2hrs in the morning on the laft side and no algea problems. I can better growth on the left side. Hope this helps you.

 

[Pickupman66]

I have 440 vho on my tank. successfully growing acropora, Montipora lps and softies. some do like the lower light. what you may be seeing (IMHO) is the corals shocked by the more intense light.

 

[Mikeyjer]

Too much lighting can cause issues! Too long of photo period will most likely to cause an algae outbreak. Too high of light causes shock, bleaching, STN, RTN, and die offs. But you should be fine with your setup.

 

[cee]

IME, too much light can actually cause browning of corals. This is, however, a generalized statement. Red acros need a ton of light and seem really bring out their colors under high light. Montis in general need less, but like all rules, there are exceptions. 6.5 hours a day here on the MH and I could probably cut back 1/2 to 1 hours.

Dave

 

[shanealanbeaty]

Thanks againg everyone. I do believe the digitata was getting way too much light, becasue I did have it at the very top of my tank right under the bulb. My ph, alkalinity, and calcium are right on. Everything else is doing great! I do not have any algae that I have noticed, thank goodness. I noticed that everyone was using supplement lighting to their metal halides. I didn't when I had I had the 55 just because of how narrow the tank was. Now that I have more room width wise, I would like to add at least one actinic bulb. What are the benefits of using supplement lighting, and cost being a factor, what would be an inexpensive way to add that extra lighting?

 

[poolkeeper1]

A T5 retro kit, Ballast, Waterproof Endcaps, Bulb and you can mount It where ever you want In a canopy. Reefgeek.com may be a good place to start looking or a LFS can get you one.