How does water depth effect lighting requirements?

[TygGer]

Im looking at two different tanks, a 72g and 90g bow front. I believe the 90g is the same dimensions, except it is about 6inches taller. If I were to go reef, how much more light would be required for the 90g???

 

[NightSpirit]

From what I understand fish capacity is based somewhat on height, so you would be able to fit the same amount of fish in the 72 as the 90. Tall tanks are generally looked down upon.

Sorry I can't help you with the lighting question, but I am sure it would require a lot more light, unless you kept the very light intensive corals near the top.

 

[malkore]

fish stock is determined main by tank volume, and tank dimensions. the reason tall tanks are 'less than ideal' is because they have less swimming space on the horizontal plane, which most fish prefer left-right swimming than up-down.
that also means less surface area at the water line, which means less space for gas exchange.

In terms of lighting, 6" is going to make a difference, IF you want corals. for soft, easy corals, you'll need 4 watts per gallon on a standard depth tank. If you place corals higher up on the rock, 4wpg should be ok ina taller tank...but if you want them low, you'd prolly want 4.5wpg to be on the safe side.
The shape of the bow front is what I dislike. I don't like how the glass distorts viewing at certain angles, the added height, the extreme added cost (a bow front here is always double the price of a standard rectangular tank of similiar capacity)...plus it's rather hard to build a curved front canopy.

Anyhow, you'd want a minimum of 360watts for a reef setup on a 90gallon bowfront.

 

[Biggen]

What are you wanting to keep in your reef tank? SPS? LPS? Softies? Clams? The reason I ask is because that question is typically more important to answer first. Then we can determine the type and amount of lights needed. Also, what are the dimensions on the 90g?

Forget about the WPG rule. It works great for FW but it is a bit "old school" as far as reef tanks go. It is more important to determine what you want to keep and what the tank size is insofar as height and length and then we can go from there.

 

[TygGer]

I'm not exactly sure what I'd wanna keep as it would be atleast a year from now...

 

[Biggen]

I'm not exactly sure what I'd wanna keep as it would be atleast a year from now...

Hmm. Well it is difficult to advise on lights without knowing what you plan on keeping. At least you have a year to think about it. I can give you a general rule of thumb though:

Lets say you want to keep SPSs and clams. I would definitely go for a MH setup. Depending on how long your tank is, you may need more than one bulb. This is because the radius of one MH bulb only has a "footprint" of about 24" in diameter. So if your tank is over 24" in length, more than one bulb would be needed.

On the other hand, lets say you go with a softie, shroom, LPS tank. You would probably be fine selecting VHO or PC lighting. The number of bulbs and wattages would, again, be determined on the dimensions of the tank.

I hope I was able to help you out some. At least you have a year to research your lighting problem and get ideas from others.

 

[TygGer]

I'm not exactly sure what I'd wanna keep as it would be atleast a year from now...

Hmm. Well it is difficult to advise on lights without knowing what you plan on keeping. At least you have a year to think about it. I can give you a general rule of thumb though:

Lets say you want to keep SPSs and clams. I would definitely go for a MH setup. Depending on how long your tank is, you may need more than one bulb. This is because the radius of one MH bulb only has a "footprint" of about 24" in diameter. So if your tank is over 24" in length, more than one bulb would be needed.

On the other hand, lets say you go with a softie, shroom, LPS tank. You would probably be fine selecting VHO or PC lighting. The number of bulbs and wattages would, again, be determined on the dimensions of the tank.

I hope I was able to help you out some. At least you have a year to research your lighting problem and get ideas from others.

Thanks! Yea, I have quite some time to think about it, but I'm imagining that I wouldn't keep anything that was difficult to maintain and require top-of-the-line lights.