Re: MH and Fluorescent efficiencies

> Re: MH and Fluorescent efficiencies
> For the MH175/U/5K (5200K) that Venture makes the mean lumens/watt
> is 51 when burned vertically and 43 when burned horizontally in a
> typical hood. The 3700K to 4300K lamps are a bit more efficient, as
> are the 250 and 400 watt versions of the 5200K lamp.
> Some horizontal high output metal halides have mean outputs of
> 80. These require a special socket. There are also regulated lag
> ballasts that deliver 90 plus lumens/watt from those bulbs designed
> to run on them. In addition there are vertically oriented lamps
> that operate on the regular CWA ballasts that get as much as 90
> lumens mean output. All of the above are 4000K lamps and have much
> higher life expectancies. Is this what you are running Steve?

No, I'm using a 5500K bulb. The largest aquarium market for these
kits is for reefs so UV radiation is very important to them. I'm
not real certain that 5500K is the ideal trade off for efficiency
versus spectrum but Rob figured I'm kind of in between a reef
customer and a pot cultivator. ;-)

> The SPX50 T-8s provide what, maybe 90 to 100 lumens/watt? Compare
> that to 43 or 65 from the MH. A MH ballast uses about 35 watts and
> a electronic ballast less than 17 (actually I think its a lot less)
> for the same wattage.
> Cost comparisons will depend upon the size and shape of each tank,
> as well one's ingenuity at sourcing the components. If it is a
> choice between 16 T-8s and 2 MHs I guess that I'd go with the
> latter.

Here are some more numbers on MH to throw in:

watts black-body initial mean   life mean        initial
      temp       lumens  lumens      lumens/watt lumens/watt
175   5200K               9000       51
250   5500K      20000   15800  2yr  63          80

The life expectancy is based on a 12hr duty cycle.


I talked to Rob at Always Lighting here in Vancouver to get these
figures and also inquired whether they were willing to entertain
out of town orders. The answer is yes but the prices and availability
can vary somewhat. The price for a 175watt system and a 250watt
system are within a few dollars. Shipping by the method of your
choice is extra. A price today for 175 watt kit including a 
parabolic reflector is about $100 Cdn because he has lots of
175watt surplus ballasts. He also has 3 250 watt ballasts. First
come first served.

The phone number is (604)520-1023 talk to Rob or Dennis.
Lighting Liquidators
811 1st Street
New Westminster BC


Ok, Karen, I guess I'll concede :-) that VHO FL is more efficient
than MH in converting electricity to light energy. I'd suggest
folks who are interested in MH to shop around locally. I would
imagine most big cities must have surplus outlets and liquidators
for this kind of stuff and for those interested in building their
own kits and capable of wiring it together, I'm sure you could
save a few bucks. MH needn't be the most expensive item in your