lighting

[jasonseaman]

i got 2 400 watt metal halide how far should i space the lights from tank?

 

[roscoe]

How deep is your tank and what type of reflectors are you using? I am running 3 400w halides in some large LB reflectors over my 270g and have them about 16'' from the water surface. I have seen them as low as 6'' from the surface.

 

[Myteemouse]

a good middle ground is 12

 

[jasonseaman]

its 20 inches deep. and the reflectors are just like closed end lol not sure just bought of someone yesterday... but 2 400 watts are not to much?

 

[ac7av]

Why run them so high?

 

[returnofsid]

800 watts of MH is going to be A LOT of light for a 20" deep tank!!! Is there a specific reason you chose 400 watts as apposed to 250 watts, or even 150 watts? I'd probably recommend keeping them pretty high, 12" or more. Otherwise, you're likely to bleach just about any corals in the tank.

 

[jasonseaman]

well to be hounest i thought about just using t5 but i got a great deal on them but i dont have to use both if one is good ill just use one and have a back up.

 

[roscoe]

its 20 inches deep. and the reflectors are just like closed end lol not sure just bought of someone yesterday... but 2 400 watts are not to much?

I don't think it is too much as I had a 400w over my 20T a while back and uit did fine. Other than that you are just burning away cash money with the power bill and adding unnecessary heat into your system. As I think you will be fine with just 2 250w with a 20'' tall tank.

Why run them so high?

You talking to me?

 

[ac7av]

Everyone answered what I was thinking. 400 watt over 20 water column seems way over kill and then to have them 15 inches over the water. Sounded like a waste of energy not to mention the heat. 250 watt at 4 inches would make more sense to me too. Half the power, less heat probably the same light in the tank.

 

[jasonseaman]

so can i run 250 watt light bulbs on the 400 watt ballast?

 

[ac7av]

That’s an excellent question. I have wondered that my self if you can downsize the bulb on a ballast or not.

I think I have herd of a 250 to 150 but not sure how that works out in bulb life or color temp.

 

[tike]

Trolling on line I found this:

A 400 Watt bulb needs to go into a 400 Watt growlight system.
All the wattages need to be the same.
Look for a manufacturer's tag on the ballast or for a stamp on the bulb to identify the type and wattage.


Sometimes you can get the wrong bulb to burn for a while, but this is a really bad idea.
The bulb will maybe burn for 90 days, maybe not, sometimes a little longer.

 

[fulkerl]

I thinkt i read some were that you could change the capisitor and it would work, the balist will even run cooler.

 

[Chichas01]

Use the right bulb and the right ballast for that bulb. You can run that 400w light, but I'd bet you could trade it for 250w setup that would better suit your needs and save you $$$.

 

[returnofsid]

No, you cannot run a 250 bulb with a 400 ballast.

 

[jasonseaman]

well thats what i thought, but i thought i would ask...