MH vs watts per gallon rule

[spiderman]

the lfs was telling me that the watts per gallon rule does not apply with MH becuase of the intensity the bulbs give off. closest to natural sunlight availible. MH 175, 250 or 400 watt all depends on the depth off the tank your lighting.
18 - 24 in. depth 175 watt bulb 24 - 36 in. depth 250 watt and can't recall the 400 watt.does all this make sense or is the lfs blowen smoke?

 

[ironreef]

depends on what you keep = sps,softies,lps. I wouldn't use 250w over 24" tall tank. Unless you keep lower light corals. sps clam that would be min. 400w for over 24" unless you have low light animals. So it depends on what you keep. IMO 24"x24" for every 250w halide would be min for most corals...if you place thme where they like = lps on the sand. If you plan on keeping lps up high then 175w would be fine 250w maybe to much. See it depends on what you keep. Sps you may have a hard time will 250w and sps on the bottom of the tank.=24" tall.

 

[nacl-h2o]

Actually the watts per gallon rule dosn't really work with any lighting. The things most people should look at are what type of corals are you going to keep, and what are their lighting needs And water depth, how deep is the water from the surface down to the top of the sand bed. And then decide what type of lighting and what strength bulb. As far as MH go I tend to agree with Ironreef on what he said only I would take those measurements from the top of the substrate to the water surface instead of the height of the tank.JMO, HTH

 

[ironreef]

yeah I shouldn't have said tank cuz you can have a 6" dsb and keep you lights 6" away or you can have 1" sandbed and keep your lights 12" away. I would factor the corals kept ,height of light from the top of the tank to the top of substrate. But that's really only important when keeping dedicated sps,clam tanks, for the most part lighting isn't everything either. i've seen colorful sps under 175w look better than under 400w= you still need good water parameter @ cal reactor, good filter = alga/skimmer ect...