What do you consider Moderate, High, Low?

Trying to figure out some coral requirements.
What do you consider "high" lighting requirement. .. 250 Watt halides?
What about 175 halides that the coral is closer to the light?
Or simply the same with lights on more hours per day?
Or I know there's the T5 fans out there too.. which I know very little about.
Then I've seen the watts per gallon suggestions... I don't see how that can be ..If you have a 500 gallon tank and only one 250 light in the middle with a single coral directly under it... I would imagine as long as the corals are getting good/proper coverage that would be all that matters??? It's not like water in far corners of a big tank are going to rob light.

 

The corals that like high light should be closer to the light and ones that don't should be farther away. It also depends on the depth of the tank!

 

T5HO's are good up to 20-24"s of depth, metal halides are a different story....

as a general rule (very general) without going into different color temps and different brands of bulbs and ballasts etc.....
150wMH good for up to 12" of depth
175wMH good for up to 15-17"
250wMH good for up to 24-28" depth
400wMH good for up to 36" of depth
1000wMH good for up to 48" of depth

 

Do you mean it would be considered "high" when you say "good for up to" at those depths and wattage?

 

Your signature says you have a 180g... 24" tall tank with 250w MH's, you can keep anything you want depending on placement. Anything "high" light would go in the top 2/3's of the tank. It all depends on what you consider as being "high". different people will say different things.

 

Without a PAR meter I think it's more trial and error.
Once you find a place where where each type of coral is happy then you have an idea where and what high-low light is
Watts per gallon is pretty useless.
also the type and amount of nutrients plus the amount and type of flow all effect how a coral will grow
Depending on these you can get away with more or less light and have a health happy tank.

 

Thats exactly my point!!! There is a lot of varibles that go in to it. Which is why one person will say one thing, and another person could say something totally different.

 

I have a 20g long that is only 12" deep. My light is a dual 96w CFL by Odyssea. One 96 is 12000K daylight and the other is True Actinic 03. I also have a lot of blue LEDs. How much light would you consider it to be? I always figured med but the guy at my LFS says I could probably keep anything under those conditions. Maybe he's just trying to get me to buy more expensive stuff. Any thoughts?

 

One thing I noticed when I switched to t5's is the light is bright across the tank. Miss the MH look, but do not miss the heat or energy bill!!

 

i have a 75 gallon acropora tank that is 21" high with 2-400w 12k halides producing 400 par on the sand and with the generic rule of thumb i should only have 175w but the sps's would not survive. using a par meter the 400w 10k produce 400-450 par on the sand and the 250w 10k produced 300-350 par on the sand depending on the brand of bulb. specific types of corals need specific par values, what types of corals are you housing?

w/gal is a generic option
w/height is a generic option
high/med/low is a generic scale based off of par values

par and k are two important factors