Too much light?

fizzlefish

fizzlefish

Member
Hello everyone. A bit new to the forums but i have lurked awhile. I recently acquired a 40 gallon breeder and a buddy of mine donated a 400-600w adjustable ballast and metal halide setup. I am using a 400w 20k bulb. It is hanging over my setup. I already know it is a bit of overkill for my tank but i figure if i raise it high enough i should be ok. I am currently cycling and dont use the light at the moment. Was trying to get some input of height of the fixture. It is hanging from the ceiling and is adjustable.

Any input would be great Thanks guys.
 
Thanks. I know it is a lot of light. It was free so i was all about saying yes. Wish i had a larger tank to use it on. LOL
 
It is not too much. I have had the same light 4-6" over the tank with SPS about 2" under the water. Height won't matter too much for the intensity - the light travels through the air fairly well... the height is more for the reflector spread.
 
I say it's only overkill if you cannot keep your tank cool.

Edit: yanking the light way up is sort of a waste. The light output drops off like a rock.

@ 18" (really anything over 13"), you would be better off using a lower wattage bulb closer to the tank. Ex: 100W at 5". It would save you a ton of electricity.

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Thanks. It is currently sitting at 8" and i had it a bit lower before. It does heat the tank up quite a bit. I might need a chiller if i use it. Sits at 80 when on.
 
That light may have been free but what does it cost $40/month for running/cooling it and the tank and your house. Get an LED and your electric will drop over $25/month. Plus you wont have to buy a $50-70 bulb every 8 months. I used to have two 250w metal halides and feel like I was robbed from truly enjoying my tank for years with them. Once I got LED's my tank just got so much nicer. Especially the colors. Check out Septembers tank of the month, all LED build and SPS dominated. MHO move into the future of this hobby and dont be a stubborn Halide guy.
 
My utilities are included in my rent so electricity is not a factor to me. I get what you are saying but right now that would be extra expense that can be used elsewhere. I am not stuck on using halide but right now it is what i'm going to be using.
 
If you are wanting to move toward the "future of the hobby," then you can wait until LEDs are actually as good as this light will be... which is in the future, because it is not now. For the time being, don't use this light if you want to consider LEDs in the near future, because you will have a basis of comparison that moving to a LED will just make you mad.

You don't need a chiller. The MH will cost you about 32 cents a day to run at 8 hours (400*8 = 3200 watts, or 3.2 kw at .10 a kw is .32 cents) or less than $10 a month. Even if a LED is $4-5 a month, your heater will run more that will use up the extra money. You can change that bulb every 12-24 months. Many LED people will buy new fixtures in that time. There is no savings in the real world. In lots of bigger tanks, sometimes even 2-4 LED panels are needed where a single 250W halide will handle the spread - in these cases, the halides are much cheaper.

I guess that I am a stubborn Halide guy, but if you are ever in Denver stop by to see some stubborn results.
 
A great way to cool the bulb is to use a cool tube or bake-a-round pyrex tube. Put the bulb inside the glass tube. Attach ducting to one end of the tube and an exhaust fan (squirrel cage fan @ 300cfm is great) at the other end and spit the air out into the attic/out a window/into another room. You can keep the bulb cool enough so that you can touch the glass tube that houses the bulb without getting burnt. Remember, for cooling pull air never push it. Pic
 
The housing i have has vents for that specific reason. I have several computer fans that i will be using for this. Thanks Ptyo.
 
You can try I dunno how well CPU fans will work. Point them all facing out so you create a negative pressure area inside the housing (air will flow in to fill the negative pressure area).

I would check the cannabis growing forums, those guys are pro at keeping HID bulbs cool (and quiet) in small spaces :P
 
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