Question about MH coverage

[leafyseadragon]

I will eventually upgrade my tank to a 75L, which is 60" wide.

It seems that the price of one MH lamp and bulb is comparable to the price of a 48" PC (4 x 65W) unit.

What I'd like to do is hang the MH light right above the center of the tank, and put an anemone directly underneath. Then on the darker regions away from the center, I want to transfer my mushroom corals.

My question is this: with just one MH light in the center, how bright will the opposite ends of the tank be given the 60" width? If it's too dark, I'll go with PCs and alter my coral selection.

 

[lando]

That really will not give you very good light coverage. Besides, your tank most likely has a center brace in the middle of it. That would cut back on the light even more. What type of anenome are you thinking of getting?

 

[loganj]

A MH bulb will cover about 24" with intense lighting. I think you'd see a big difference in the intensity of the light over a 60" span with one MH in the middle. It really depends on what you want to keep in the tank. If you are going to primarily keep low-med light corals, I'd go with the PC's. If you want some animals with high light requirements, I would look into at least two MH bulbs. JMHO.

 

[leafyseadragon]

Thanks to both of you for your advice.

It's really not a question of which corals I want to keep. The issue is how much money I have to spend on lighting (not enough for 2 MH fixtures), which will restrict my choices of corals. Since the price of one MH fixture and the 4 bulb PC are close, I was just wondering if I could get away with one MH, but it sounds like the ends of the tank will be too dark?

Since I am just starting out with corals, I prefer the more durable species that don't require large amounts of lighting. But with a 260W PC for 75 gallons, that's 3.5 watts per gallon. Is that enough for low to moderate light corals?

 

[piggybank2005]

Don't upgrade to MH unless you are abosultely sure it is your last light equipment on that particular tank. A mistake can be costly when it comes to MH lights.

 

[fishfreek]

Remember MH is a single point of light source where as the PC is florecent and you get the same light output thru the entire lenght of the bulb. If you do indeed have that center brace the MH light over it will look very bad. For an idea take a 2" wide bit of paper and hold it under a incadecent light and see the shadows it casts.

The reason florecent bulbs dont cast a shadow when they are over the center brace is because the light is also being output on the sides of the bulb that is not over the brace and that light cancels out the shadow being cast by the brace.