Using a 24" hood on 30" tank?

[sturnmeyer]

Hey all....

 

I'm thinking about upgrading my Coralife PC hood to a MH/PC combo hood. The problem is it is on a 30g tank that is only 30" wide. The pc hood I have is 30".

 

Do you think I could use a 24" MH/PC combo hood on this tank? I would be hitting roughly 9 watts per gallon with the one I'm looking at.

 

Also, if I did that, should I go 10K 15K or 20K?

 

Thanks,

Scott

[Jon Lazar]

As far as the width goes, there's no rule that says you must have full strength lights right up to the very edge of your tank. You'll just have less light at the ends. So put some less light-demanding corals there. Lots of aquascaping involves leaving some "white space" on the sides of the tank anyway. Temporarily move your current hood 3 inches to the right and see what it looks like at the left end of your tank.

 

Jon

[flowerseller]

As far as the width goes, there's no rule that says you must have full strength lights right up to the very edge of your tank. You'll just have less light at the ends. So put some less light-demanding corals there.

:D

Well put!

[craby]

I am using (2) 24" VHO's on my 36" long FW tank setup (3'lx2'dx3't). I prefer having the reduced light on the vertical glass as it causes less algea to grow on the glass.

[davelin315]

It also depends on the hood itself. If it's not quite wide enough to physically cover the tank, it doesn't mean that the light won't get there. If you're using a metal halide bulb, it's not like it's going to be a smaller bulb for a 24" vs. a 30" hood. The bulb will be the same length and wattage, as will the reflector. The PCs might be a different wattage and a bit smaller, but they're only their for aesthetics really and adding some blue to your light color. Because you do have this actinic supplementation on that hood, I would go with the 10,000K bulb, by the way, as the others will be much bluer already, so why supplement them and sacrifice some of the intensity? In the end, you'll get the same coverage from the halide bulb, and the only real difference will be the PC lamp coverage which is not going to make a difference in the end for your photosynthetic needs. Take a look at the comparisons between a 30" and a 24" MH/PC combo hood. You'll see that the MH is typically exactly the same, as is the reflector for it, and the only difference is typically in the wattage of the PC and therefore the reflector and length is different there. Of course, it'll be 3" shy of covering the tank on either end, but you probably aren't going to sit a MH fixture on top of your tank anyway and they normally are hung from the ceiling or mounted in the canopy.

[sturnmeyer]

Thanks everyone....