[numisticman]

Join Date: Dec 2008
Posts: 2
Is there such thing as too much light?

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Hello,
I have been messing with salt water aquariums for about a year and a half.
I have a question about lighting. I am currently running 2 150 watt 10000k metal halide lights on my 90 gallon, everything is doing great, but it seems that it could use just a little more lighting. I recently scored on 2 complete lighting fightures that consists of 2 brand new 400watt 15000k metal halide bulbs (mogul base) 2 brand new reflectors with screw in bulb holders, 2 brand new ballasts and all of the needed cords. I will need to make a canopy for these lights.
My question is. Is there such thing as too much lighting? I know that these bulbs will produce way may heat and I will have to keep on eye on the water tempature. but am I going to harm my coral or fish? or are there other concerns that I should be aware of?

Thank you for your time

Num.

[BLKBRDTA]

Hello Num, great to have you join us here at ReefBuilders.com! I think I may be able to help you out a little bit here.

Assuming your 90 gallon tanks dimensions are somewhere around 48"x18"x24" Then obviously, yes you would need a 48" long ballast. Now in terms of the amount of light versus the amount of water you would want to go anywhere in between 408 Total System Watts all the way to 692 Total System Watts, depending of what kind of growth is in the tank e.g. Soft Corals, LPS & SPS corals and live rock. I would stick with light sets in between 458-692 Total watts personally.. Next up, are the different bulb combos you can arrange, which I will list here:

MH = Metal Halide

CF = Compact Florescent

T5 = 460nm Actinic Blue

-48" 2X175W MH, 2X54W T5 (458W total)

-48" 2X150W MH, 4X54W T5 (516W total)

-48" 2X175W MH, 2X96W CF (542W total)

-48" 2X150W MH, 2X130W CF (560W total)

-48" 2X250W MH, 2X96W CF (692W total)

Also I would recommend striving for a setup that comes with pre-installed Lunar Lighting, as this helps greatly with natural rhythmic cycles, sleep patterns, feeding and spawning (just a personal recommendation, not a necessity.)

If you have 2x400W MH, that may be too much however. 800W isnt exactly what to be concerned about, but the amount of Gamma rays that Halides throw off can be dangerous with that much power IF a proper UV screen isnt applied over the tank. I would maybe keep 1 MH in and go with either 1 48" T5, or CF.. And yes, your water will heat up, sometime small amounts, other times large amounts. So constantly check temps, preferably with a Digital Thermometer.

Well I think I answered most if not all your questions Num. And if I didnt, feel free to ask any others that you may come up with. Hope this information was of some use to you.

See you in the forums!

Tony

[unclejed]

Hello Ray, Tony gave good info but I thought I would turn you on to this article to give you a better understanding of lighting for the aquarium; OceanReeFlections Marine and Reef School 101

[BLKBRDTA]

Great link Jed, very very helpful on the breakdown of the different types of lighting. Even I learned somethings.

[numisticman]

Tony,
First of all I want to thank you for the information!!!!!!!!!
It was very helpful!!!!

and thank you unclejed for the link!!

I do appreciate the help!!!
Num

[BLKBRDTA]

No problem Ray, post up some pictures when you finally decide on your combo and get it all just right. I will post some new pics of the Lunar lights I just ordered soon.

Glad we can be of assistance to you, again, remember that if you need advice for anything else just private message us or post another thread.. Im sure we'll find it.

See you in the forums!

Tony

[danielcherian]

Tony-- I don't think the UV rays are an issue with the 2x400w MOGUL socket halides since they are already shielded (but I could be wrong?).

If you can keep the light fixture high enough off the water and provide sufficient ventilation, over-heating may not be an issue. Your problem has more to do with controlling heat than providing too much light- raising a fixture a few inches dramatically reduces the amount of light penetration, but would still present issues with over-heating.

What are your tank dimensions? Soft corals would need to be kept at the bottom. SPS in the middle and top.

[BLKBRDTA]

Daniel, you have a good point there, 2 400's could be an option. However 700W of lighting is the maximum recommended for keeping LPS, and SPS, although 800W probably wont do much damage either way. Your right with the positioning of each type, from the bottom, to the surface. I have a 50g, with 1x250W MH and its plenty strong enough for anything in there, and even will output all 4 T5's. Thats is why I have a complete dawn/dusk cycle set up, because the Metal Halides are so strong that if they turn on immediately at dawn, the corals AND fish will go into shock from the extreme spectrum shift. And thats what I was stressing the most to our friend num here.

[WILLIAM1]

The only concern I would have os the heat issue. Might consider having them about 16-19" above the water. Im installing a lumenbight with a 400watt over my 60gallon cube soon. But I have a chiller on stand by. I think the light would be awsome.

[numisticman]

Hey all,

Once again I thank you for the Information!!

This place is great!!!!!

[BLKBRDTA]

Hey Num,

I completely agree with you, its an all-in-one saltwater dictionary!