Can somebody explain to me the difference on MH

[SalteeDogg]

I am about to upgrade to metal halide lighting and was wondering what the difference between regular and hqi is? Is it the same thing? Sorry for the stupidity but I have always wondered.

[bobby]

I believe all HQI is is DE (double ended) bulbs. I think the double ended bulb wear out faster but can't say for sure. I seen a thread on it before and not one person said they were better than SE.

[poolshark181]

Originally Posted by bobby

I believe all HQI is is DE (double ended) bulbs. I think the double ended bulb wear out faster but can't say for sure. I seen a thread on it before and not one person said they were better than SE.

on the contrary, i read that DE bulbs last longer and have a better light spectrum than Single ended bulbs.

[fatman]

An HQI is a name put to lamps requiring a special ballast, the M80, which is a standard ballast in Europe. HQI can not be used with a american standard M58 ballast. DE nomenclature refers to the type of tube ends, meaning the "doubled ended," rather than the single ended "SE" which refers to receptacles for the mogul or standard screw in sizes bulb ends. The HQI is supposed to be more intense lighting, and allegedly lasts longer than the double wall tubes of US standards. However, the HQI being a single walled tube lacking the alleged double tubed UV protection requires a UV shield on all lighting fixtures. Which is pretty insane as the second outer tube on most American Halide lights block virtually none of the UV lighting. The HQI also has no dimple in its emitter bulb, and no metal bars to block light output as do American standard halide bulbs. The American standard tube is cheaper as are the M58 ballasts for them, and there are many more choices in the color range and number of manafacturers for American standard bulbs. I use a lot of the 250 watt HQI's, and only have 400 watters in standard tubes for standard ballasts.

[SalteeDogg]

I found a good deal on 2 400 watt retro fit kit. Is that too much for a 75 gallon? It will have two 54 watt actinics as well.

[ccCapt]

Overkill for a 21" deep tank...not to mention the heat issues.

[fatman]

A 150 gallon or a 210 gallon would be better candidates for 400 watt halides. With a 21 inch deep tank with a moderate sand bad even 150 watt halides with T-5 actinics would be good. I would prefer 250 HQI and T-5 actinics, but I am principally only concerned with SPS coral.