Lighting Watts Myth or Fact?

[scarolinaguy20]

Everywhere on-line says that for most anemone and corals that there is an equation:
3-5 watts per gallon
This doesnt make sense. If I have a 30, 55, and 75 gallons that are all 18 inches tall, they should need the same amount of lighting.
The equation should be based on the height of your tank.
If I have 30 gal tank that required at least 90 watts. So 90 watts shines through 18 inches of water and everything is good. So why cant 90 watts keep alive something in a 75 gal tank that is 18 inches tall? It can and does!
Petland Pet Shop in Fort Walton Beach, FL proves this! They have a 100 gallon display tank with nothing but corals (all types) and anemone; they only have hagen 48" x2 54 watt t-5 (108 watts total) and they all are healthy and in great condition. That is a 1 to 1 equation? How is that?
One last question to the non believers. If I have two 100 gallon tanks; One is 18 inches tall and one is 6 inches tall, will I need the same amount of light?
You need more light to go deeper into water. This is why corals and anemone grow mostly in shallow waters. The shallower the water the more light shines through.

 

[greg9871]

Originally Posted by scarolinaguy20
http:///forum/post/2662788
...One last question to the non believers. If I have two 100 gallon tanks; One is 18 inches tall and one is 6 inches tall, will I need the same amount of light?
You need more light to go deeper into water. This is why corals and anemone grow mostly in shallow waters. The shallower the water the more light shines through.
im guessing on this but i would assume that you would need close to the same amount of watts because even though you have less distance to go down you have to span a bigger sq. ft. area to still have 100 gallons, and that would mean more lights which would add more watts. right?

 

[payton 350]

myth....you are correct (at least i believe) in your assumption that light penetration will be the same at 6 inches whether you have 30 gallon or 300 gallon.
It's not the wattage but the intensity (lumens) of the spot where the coral will be that matters

 

[coachklm]

Even though this has been explained multiple times...
It still remains a myth all above are correct lumen's,spectrum and height should be the only things that matter.

 

[bang guy]

I disagree with lumens being relevant. Lumens are a measure of how bright something is to human eyes, it is not measure of the amount of light.
PUR or PAR are relevant measurements. Spectrum and Color (Kelvin) are not very relevant either in my opinion.
It's the amount of light (MicroEinsteins) being received.

 

[perfectdark]

Originally Posted by coachKLM
http:///forum/post/2663413
Even though this has been explained multiple times...
It still remains a myth all above are correct lumen's,spectrum and height should be the only things that matter.
+1
different bulb types have different lumen per watt out put, thus making them capable of projecting their PAR rating to certain depths. Std CF, or PC have the least amount of lumens per watt, HO T5's in the correct set up can rival that of metal halides until you reach the 24" height area. And from there on out its Metal halides... Tank height plays a very important role in determining how many watts of what type of light needed.

 

[scarolinaguy20]

I just think alot of people buy hundreds to thousands of dollars of lighting and really dont understand what they are trying to accomplish. I just wanted people to know that 3-5 watts per gallon is a ballpark figure to be extremely safe but not really necessary. Lighting is probably one of the most expensive parts and least understood part of a tank.
I do highly recommend the Hagen 48" t-5 54w x2 because they are everything I need. I almost spent $300 more to follow the 3-5 watts per gallon rule, and Petland showed me it isnt necessary. I did research and this 3-5 rule is a myth in my opinion. Watts is the amount of electricity, not lighting (i think). If I put a regular 60w light bulb above my tank would that count? NO It is the Lumens and other aspects.
Thanks for your imput. Cause I am new to this and just looking for some answers.

 

[payton 350]

Originally Posted by Bang Guy
http:///forum/post/2663435
I disagree with lumens being relevant. Lumens are a measure of how bright something is to human eyes, it is not measure of the amount of light.
PUR or PAR are relevant measurements. Spectrum and Color (Kelvin) are not very relevant either in my opinion.
It's the amount of light (MicroEinsteins) being received.

PAR is what i meant......terminology gets me confused sometimes ...but i think you get the point.
Thanks for correcting my mistake.