MH vs HQI

[stonepilot]

tank will be 18 inches deep, but my real question is which do you feel is better and why. thanks for all help

[lReef lKeeper]

HQI is metal halide, HQI is a type of MH bulb, it has 2 ends like a halogen bulb. but IMO i like the screw in bulbs.

[jerryc]

DE double end MH will put out a little more but run a little hotter and as a rule
cost a Little more to sit up. Also has to have a shield i thank this may offset the increase in light output.
SE will run a little cooler and less expensive to set up and more widely available.
personnel i like the SE better myself.

[dakar]

DE reflectors tend to have a much more narrow concentration of light (smaller footprint). The SE bulbsreflectors tend to have a more spread out patterning.

[davejnz]

Dakar summed it up nicely.DE's have a smaller diameter than moguls and therefore can be fitted in a small reflector/fixture that has a tighter focused spread.Better,IMO they both have their applications which might make one or the other "better".In a shallow tank such as yours,I'd go with a mogul MH in a spider/parabolic reflector.These reflectors can be flared out to spread the light even more.One of the claims with HQI/DE is they have a longer bulb life.I use Iwasaki mogul MH's and could easily get 18months out of one.Anyways,1yr seems to be the popular opinion on when a MH should be changed.