Mercury Vapor bulb?

Ok, so i'm looking thru my friends old stuff and i find a spare bulb with his old light. The markings on the bulb show its a 400 watt bulb and since it says Hg on it in a circle i can only assume its a mercury vapor bulb.

I cant seem to find the bulb online but the markings on it are as follows:


SLi
400w
Belgium
LU400 S51

45

Then Hg in a circle.


Anyone have any info on this bulb? and a recommendation for use, veg, flower?

You, sir, are the proud owner of a 400 watt HPS bulb. SLi is Sylvannia's commercial distribution branch, which has a plant in Belgium. LU400 is the model number of a 400 watt HPS bulb. Enjoy.

so wait, is it Mercury Vapor or HPS?

i'd like to know also cause the state surplus here has a few 400w MERCURY VAPOR bulbs for $5 each.... is that HPS? but these are like 4in in diameter... don't think its an hps

It's a High Pressure Sodium (HPS) bulb. The Hg symbol is there because HPS bulbs contain mercury, an element that must be recycled properly.

Mercury Vapor and HPS are very different. HPS grows plants, MV does not.

back in the old days the pioneers of indoor growing used mv lighting, but those days are long past hps mh t5 and even hps/mh conversion bulbs are the norm now-a-days. mv is very inefficient, and is best used for street and security lamps, not plants

thanks for clearing that up for me.

i've never seen a hps/mh conversion bulb how much more efficient are those compared to just hps?

well it depends on how you grow, if you use the same space for flowering and veg then they are conveinent because they allow you to run a single ballast yet still have metal halide and hps light. for example say you have a closet and a 400w hps ballast bulb and a nice hood for it.....you could then purchase a hps/mh conversion bulb and be able to have the blueish light of the mh and still run your hps ballast. these bulbs do loose a bit to power and lumen output in the mix compared to a mh system but not enough to worry signifigantly about. they also have mh/hps bulbs which allow you to do the same thing, only vice/versa. But if you have two seperate areas for flower and veg then you would probably be just as well off without any type of conversion bulb unless you want to grow more plants at a time....

yea from how that sounds i dont think i'd be around a setup anytime soon that would really benefit from conversion bulbs, it seems it would just be easier to stick to whats already around.. thanks for the info tho guys.