Help me understand a little better about lights

[symonsay]

I will be setting a tank in a few months when i move to my new home, i'm new to saltwater and have been reading books and forum to try to get as much knowledge as i can get, i'll set a FOWLR but might eventually get some corals, maybe the lowest maintenance i don't know, but i need to clarify something like i did when i was planting my freshwater tank. I have read that you need about 4-5x watts per gallon, but isn't more important depth of the tank than the gallons it have??
for example, a 75g tank is L48xD18xH20 but what if i custom made a tank that is L48xD24xH20 they have the same depth and light should penetrate the same cause volume of water won't matter in this case, or water volume will affect how the lights goes into the water and to the corals??

 

[nikesb]

wattage is no longer the an accepted method for lights.
its about par settings now. imo, 100-200 par on the sandbed for a 20" tall tank is a good number.
if you want penetration, led + good optics will get you some strong par on your sand bed. another strong fixture are ATI t5 fixtures. they will put out 200+ par on a 24": tall tank. metal halides with good reflectors will also attain these numbers.

 

[symonsay]

Thanks, for a 20" what T5HO lights should i use and how many??

 

[nikesb]

24" tek 4x24w t5-ho would be a good option.

 

[symonsay]

my plan is to custom build a tank that is 20" deep with a base of 48x24, in these case will 4x48" 54w T5HO still be a good option??

 

[nikesb]

oh i thought u meant 20" length. for a 20" deep tank, a 4 bulb option would be good, but a 6 bulb would be better