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drjay50000
Guest
My question is will mh 800w 10000k be ok on a 90 gal tank? Is this to much light? I also hear that to much light on your tank and the only thing that grows fast is the algae. anybody know?
spiderwoman
Active Member
Do you mean you have 2 400W bulbs?
scsinet
Active Member
Well there is certainly a point of diminishing returns when it comes to aquarium lighting, and I'd say you are well over it.
The question is... what exactly are you trying to accomplish with that much light? If it's that you have access to 400W light fixtures you want to use, be sure to consider the high costs of operating the fixture, aside from the fact that I can't see how you'd avoid investing in a chiller. If that's the case, the operational and peripheral costs will almost certainly dwarf the "savings."
The question is... what exactly are you trying to accomplish with that much light? If it's that you have access to 400W light fixtures you want to use, be sure to consider the high costs of operating the fixture, aside from the fact that I can't see how you'd avoid investing in a chiller. If that's the case, the operational and peripheral costs will almost certainly dwarf the "savings."
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drjay50000
Guest
I have two 400w bulbs. It’s not that im trying to accomplish something by using both of them I just wanted to know if I could. But if its not a great idea and going to cost an arm and a leg to run I could only use one. It’s a 90gal tank so if I put one in the middle it should look fine right? I have a 265gal tank that the light came on in the first place; but I’m going to turn that one into a freshwater tank. I don’t want to waist the lighting, but I don’t want to overkill the tank either. The 90 gal is the saltwater tank about to turn reef tank depending on what you guys think or coarse.
scsinet
Active Member
It *may* look right over a 90g tank. Halides look best when placed about every 24". You may end up with a dark area on the sides. Of course with that light, you could place it higher above the tank.
As far as a cost to run, assuming a 0.09/KWh rate, and a 10 hour lighting cycle, the (2) lamp 400w system would cost about $262/year to operate. A dual 250w system would cost about $165 in that same time period. So that's $100 per year you are saving in electricity. In 3 years, you'd save enough to buy a properly sized fixture. Don't forget though, you can't just change the lamps, you need to change the ballasts as well.
As far as a cost to run, assuming a 0.09/KWh rate, and a 10 hour lighting cycle, the (2) lamp 400w system would cost about $262/year to operate. A dual 250w system would cost about $165 in that same time period. So that's $100 per year you are saving in electricity. In 3 years, you'd save enough to buy a properly sized fixture. Don't forget though, you can't just change the lamps, you need to change the ballasts as well.
ameno
Active Member
This is an interesting thread, because I have the same problem, I got a free hamilton fixture with (2) 400 watt 10000k bulbs and (2) two 96 watt VHO. That I would like to use on a 90 gal. frag tank.
I have been wondering if it would be possible to go down to 250 watt on the MH bulbs with the same balast, I know I have done this before with flood lights but wasn't sure on this type light, but I guess what you are saying is you have to use the same wattage bulb that the balast is designed for and you cannot go down it bulb size?
I have been wondering if it would be possible to go down to 250 watt on the MH bulbs with the same balast, I know I have done this before with flood lights but wasn't sure on this type light, but I guess what you are saying is you have to use the same wattage bulb that the balast is designed for and you cannot go down it bulb size?
spiderwoman
Active Member
You need a different ballast if you change the bulbs. Unless your ballast says it's for 250/400, then you can't just switch bulbs.
I thought I went too far with 2x400W on our 150g tank hehehehe.
I thought I went too far with 2x400W on our 150g tank hehehehe.
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drjay50000
Guest
Ok, so i know its not that great to run 800w to a 90g tank but i can do it right? if money is no object. how high up do i have to place the fixture in order to not effect the temp of the water to much?
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drjay50000
Guest
That's a long way up! How much light will be wasted that far up? I just built it today and i have it about a foot off the water, but i haven't turned the lights on for a full day yet so I'll keep you informed on how it goes. I don't think it will be that bad because it's not covered up or anything so the heat can escape.
coral keeper
Active Member
Originally Posted by drjay50000
http:///forum/post/2883501
That's a long way up! How much light will be wasted that far up? I just built it today and i have it about a foot off the water, but i haven't turned the lights on for a full day yet so I'll keep you informed on how it goes. I don't think it will be that bad because it's not covered up or anything so the heat can escape.
If there is no live stock and just water, I'd try it at 1ft, if it heats up, raise it some more, if it heats up, raise it some more, ect, ect.
http:///forum/post/2883501
That's a long way up! How much light will be wasted that far up? I just built it today and i have it about a foot off the water, but i haven't turned the lights on for a full day yet so I'll keep you informed on how it goes. I don't think it will be that bad because it's not covered up or anything so the heat can escape.
If there is no live stock and just water, I'd try it at 1ft, if it heats up, raise it some more, if it heats up, raise it some more, ect, ect.