400w MH too much?

inovrmyhd · 09/22/2008, 10:38 AM

I have a 400w MH light from a DIY projector I had made. I was wondering if it would be overkill on a 29g tank. the dimensions of the tank are 30w x 12d x 18h. My thoughts are that it would be too much but wanted to get some other opinions before spending money on a smaller light.

livingstone · 09/22/2008, 10:51 AM

Well, if you hung the light from the ceiling and lit the whole room with it too...

Michael · 09/22/2008, 10:53 AM

i would have thought 8-10 watts per gallon on a tank your size would be ample, so probably a little large for a 29

fivesmallworlds · 09/22/2008, 10:58 AM

Way Overkill!!! Unless you really want a 95 degree algae display. It could be nice... lol

Good excuse for a tank upgrade though...

Poorcollegereef · 09/22/2008, 11:16 AM

is it too much light... no, but you could be more efficient

the 400w will be a electric bill concern as well as a heat problem. A smaller light could do the job, but s you want sps growth the a 400 is better

I had a 400w over a 20L for a few months before I upgraded to a 65g... which now has two 400w pendents.

Honestly, I dont know if you would recover the cost of a smaller light. Assuming a 10h photo period at 12 cents a kWh, A 400w lamp will use $14.6 dollars of energy a month, 250w is $9.1, and $5.5. Next if we assume the cost of a new pendent (ie Aquamedic) at $286 for the 150w and $310 for the 250w, then it will take 57 months of use (over four years) to reclaim the cost of the pendent. For the 150w, it would take 32 months, or two years and 8 months to recoup the cost of a new lamp. Now the cost of a kWh and the fixture will vary but the 400w will give you better growth, but have heat problems unless you mount it high, run a fan or chiller

inovrmyhd · 09/22/2008, 11:37 AM

Thanks everyone for your replies. I was thinking of hanging it about 2.5 feet above the tank and I already have a cooling fan on the tank (Wife doesn't like to use the AC in the house). I was also going to make my own fixture with a fan in it.

So I guess the conclusion is that I could use it if I really wanted to but it's not the smartest choice. I think I'll keep an eye out for a used smaller system and stick with my 48w t5 and 30w t12 that I have on for now.

chrisqueenz · 09/22/2008, 11:39 AM

Heat will be a problem. That size light could heat a 29G tank pretty quick. How far off the tank are you planning to hang it?

inovrmyhd · 09/22/2008, 11:50 AM

Chris: We may have replied at the same time. See the post above yours.

Poorcollegereef · 09/22/2008, 03:48 PM

2.5 feet above the aquarium is not going to be a major problem, unless it is a enclosed/hooded set up. I think you will be fine, but the MH may heat up the room a bit. Nothing major, but it may be a degree warmer than normal. Goodluck inovrmyhd

Bonneville08 · 09/22/2008, 04:59 PM

Have you considered a compatible bulb of a lesser wattage?
Just a thought.

inovrmyhd · 09/23/2008, 06:19 AM

Bonneville: I may have to try that. If I go that route I will probably just buy a new setup since my 400w is running off a transformer and capacitor instead of an electronic ballast. If I'm going to go with lower wattage I may as well go with a ballast that will save me even more money on the electric bill. Anyone have any suggestions on what wattage I should go with?

09/22/2008, 10:38 AM	#1
inovrmyhd Registered Member Join Date: Sep 2008 Location: Scranton, PA Posts: 103	400w MH too much? I have a 400w MH light from a DIY projector I had made. I was wondering if it would be overkill on a 29g tank. the dimensions of the tank are 30w x 12d x 18h. My thoughts are that it would be too much but wanted to get some other opinions before spending money on a smaller light.

09/22/2008, 10:51 AM	#2
livingstone Registered Member Join Date: Jan 2001 Location: Oneonta NY Posts: 222	Well, if you hung the light from the ceiling and lit the whole room with it too... __________________ Dan Current Tank Info: 150 'cube'

09/22/2008, 10:53 AM	#3
Michael NTTH Rookie Help Join Date: Jan 2008 Location: Gloucester, England,UK Posts: 7,808 Blog Entries: 6	i would have thought 8-10 watts per gallon on a tank your size would be ample, so probably a little large for a 29 __________________ Don't be afraid to ask questions, we in the new to the hobby are here to help you [For My Tank Spec,Photo Album,Articles and website, click on my name] MY Very Kindest and Warmest Regards , MIKE Current Tank Info: I have a 92 gal Corner Tank, and way too many pieces of equipment to list really, (proud member of the reef central corner club)

09/22/2008, 11:37 AM	#6
inovrmyhd Registered Member Join Date: Sep 2008 Location: Scranton, PA Posts: 103	Thanks everyone for your replies. I was thinking of hanging it about 2.5 feet above the tank and I already have a cooling fan on the tank (Wife doesn't like to use the AC in the house). I was also going to make my own fixture with a fan in it. So I guess the conclusion is that I could use it if I really wanted to but it's not the smartest choice. I think I'll keep an eye out for a used smaller system and stick with my 48w t5 and 30w t12 that I have on for now. __________________ -- Tim -- Current Tank Info: 29gal, LS, LR, Yellowtail Damsel, Lawnmower Blenny (RIP), false percula, shrooms, candy cane, anemone, eagle eye and radioactive dragons eye zoas

09/22/2008, 11:50 AM	#8
inovrmyhd Registered Member Join Date: Sep 2008 Location: Scranton, PA Posts: 103	Chris: We may have replied at the same time. See the post above yours. __________________ -- Tim -- Current Tank Info: 29gal, LS, LR, Yellowtail Damsel, Lawnmower Blenny (RIP), false percula, shrooms, candy cane, anemone, eagle eye and radioactive dragons eye zoas

09/22/2008, 10:58 AM	#4
fivesmallworlds Registered Member Join Date: Mar 2008 Location: Minnesota Posts: 255	Way Overkill!!! Unless you really want a 95 degree algae display. It could be nice... lol Good excuse for a tank upgrade though...

09/22/2008, 11:16 AM	#5
Poorcollegereef Future Doc Join Date: Jan 2006 Location: DC Posts: 961	is it too much light... no, but you could be more efficient the 400w will be a electric bill concern as well as a heat problem. A smaller light could do the job, but s you want sps growth the a 400 is better I had a 400w over a 20L for a few months before I upgraded to a 65g... which now has two 400w pendents. Honestly, I dont know if you would recover the cost of a smaller light. Assuming a 10h photo period at 12 cents a kWh, A 400w lamp will use $14.6 dollars of energy a month, 250w is $9.1, and $5.5. Next if we assume the cost of a new pendent (ie Aquamedic) at $286 for the 150w and $310 for the 250w, then it will take 57 months of use (over four years) to reclaim the cost of the pendent. For the 150w, it would take 32 months, or two years and 8 months to recoup the cost of a new lamp. Now the cost of a kWh and the fixture will vary but the 400w will give you better growth, but have heat problems unless you mount it high, run a fan or chiller

09/22/2008, 11:39 AM	#7
chrisqueenz Registered Member Join Date: Jun 2006 Location: Rochester New York, USA Posts: 2,042	Heat will be a problem. That size light could heat a 29G tank pretty quick. How far off the tank are you planning to hang it?

09/22/2008, 03:48 PM	#9
Poorcollegereef Future Doc Join Date: Jan 2006 Location: DC Posts: 961	2.5 feet above the aquarium is not going to be a major problem, unless it is a enclosed/hooded set up. I think you will be fine, but the MH may heat up the room a bit. Nothing major, but it may be a degree warmer than normal. Goodluck inovrmyhd

09/22/2008, 04:59 PM	#10
Bonneville08 Registered Member Join Date: Sep 2008 Location: Goodyear, AZ Posts: 513	Have you considered a compatible bulb of a lesser wattage? Just a thought. __________________ Edge you mah cating myself Check out my gallery if you desire. Current Tank Info: 50 gallon mix of soft, LPS and SPS, two croceas, two maximas, a few fish, turf filter with skimmer, MH and PC lighting, chiller, Calcium Reactor and wave2k.

09/23/2008, 06:19 AM	#11
inovrmyhd Registered Member Join Date: Sep 2008 Location: Scranton, PA Posts: 103	Bonneville: I may have to try that. If I go that route I will probably just buy a new setup since my 400w is running off a transformer and capacitor instead of an electronic ballast. If I'm going to go with lower wattage I may as well go with a ballast that will save me even more money on the electric bill. Anyone have any suggestions on what wattage I should go with? __________________ -- Tim -- Current Tank Info: 29gal, LS, LR, Yellowtail Damsel, Lawnmower Blenny (RIP), false percula, shrooms, candy cane, anemone, eagle eye and radioactive dragons eye zoas