Metal Halide Bulb Replacement

[onlyartificiallight]

I have a 400W MH fueling my orchid frenzy but I wonder, how do you know when its time to replace the bulb. The footcandles are starting to lessen a little i think and I have had the bulb for quite sometime, but is there a definitive way to tell?

Also, when replacing the bulb, what should I look for? Are there different types of MH bulbs, some better for growing?

[dennis]

it all depends on how long you have used it they run usally around 12000 hours but should be replaced brfore that time is up. you want to make sure you have the same type as in vertical ,hortizontal or a universal which can be operated in both ways. myself i prefer the hortlilux brand but you could also go with a conversion type that would give you some of the red spectrum instead of all blue

[camille1585]

In the company where I am doing my internship I think they change the bulbs every 12 to 14 months depending on how long they have them running. Most of them are on 16 hours a day most of the year, but a bit less in the summer when natural light is sufficient part of the day.

[onlyartificiallight]

yeah im thinkin its time 4 a replacement. dennis are those hortilux bulbs something you can mail order or do i need to find a supplier near me?

oh and what do you mean by 'conversion type"? is like a sodium that works with metal halide balast/socket?

[Ocelaris]

One way to just qualitatively tell how old a bulb is by looking at the salt deposits in the arc tube. The older it is, the blacker it is. here is what a new 400w bulb looks like:



I think this is a 175w bulb (new)




If you have decided to replace your bulb, I would reccomend you find out what ANSI standard your ballast is, so you can pick a bulb that is compatible. Usually the best way to tell is to look at the ballast and it should say like M81, M102, M101 etc... Once you know that, you can pick a bulb. If it's not on the outside, you may have to take off the ballast cover. If it's heavy, it's a core and coil (old school magnetic) and just don't touch the bare wires, but you can definetly see from the top of the "core" part. Of course unplug it before attempting any of this.

Hortilux bulbs sometimes use special ballasts, or will run on regular ballasts but not at full brightness or with a shorter life span. There are just too many variables to be able to just pop in any 400w Metal halide bulb. For example there is pulse start and probe start. One will work in the other, but the other will blow up the first...

Typically any "grow" store will give you a compatible bulb, if you go for the lowest common denominator, but you can shop around for a good bulb.

I am using two high color rendering 4000k bulbs which run on HPS ballasts, but are Metal Halide... not quite a conversion bulb, they're the pulse start type, a newer better technology. Hope this helped and didn't make too many new questions.

[onlyartificiallight]

awesome thanks for the info. my old school heavy ballast says M59 bulb only. luckily thats the 400w bulb on hortilux's website so im thinkin ill be good to go with that. my light is still on so ill have to check tomorrow morning for those black salt deposits....

[SheilaJ]

I'm not sure what I should be looking for - do you have a pic of an old bulb for comparison?

[Ocelaris]

hortilux is a generic term for a "plant bulb" there are probably 20 hortilux 400w M59 bulbs...

My personal reccomendation would be the EYE lighting bulb, namely Iwasaki...



EYE Hortilux Metal Halide
EYE Hortilux Ultra Ace
EYE Hortilux BLUE

Hortilux is a sales pitch, not necessarily a determination of the value of the bulb. Especially when viewing plants is concerned, I reccomend a bulb you can live with looking at the plants. This means a bulb with a relatively "cool" temperature in the 4000-6500k range. Also the Photosynthetic Active Radiation is different for various bulbs. The more green, the less useable light the plant has.

My personal favorite in a M59 quartz bulb is the Iwasaki "clean arc" 6500k bulb, it has a CRI of 90, meaning near perfect color rendering which is important for actually seeing the plants accurately. Also has the one of the highest PAR rating of any bulb.

EYE CLEAN ARC - HIGH COLOR RENDERING (DAYLIGHT)

There is a lot of glimmer and glammer in bulbs, lots of hoopla and false information. A decent bulb will grow just about as good as any other, and there' no reason IMO to spend the extra money on a "hortilux bulb" because they're not necessarily any better.

Here is a good article, you can see some of the "hortilux plant bulbs" indeed are worse that a good Everyday use Metal Halide bulb! There are so many other factors which will decide the health of the plant than color specturm, people make a lot over nothing. Priority wise, the Amount of light is first (i.e. wattage and lumens), second the reflector, third the distance and temp, and only after all those factors are optimized would I even bother with spectrum. Just because it's easy to buy and plug in, means you're probably not going to get a huge boost from changing one bulb for another "hortilux". A new bulb is good, but from one to another decent bulb isn't going to make a huge difference in my experience. It would be impossibly to quantify anyways.

Aqua Botanic-light bulb comparison

[onlyartificiallight]

hey thanks for the clarification. i thought hortilux was a brand i was actually looking on those sites though since thats the 1st that comes up under google search. now ill be checkin my local grow store for either the clean arc or the hortilux BLUE.

my bulb is in fact showing black where in your pic is like a light brownish yellow. sheila i tried to tak a pic but it came out unfocused...

[Ocelaris]

yeah, various levels of black in the arc tube are basically the filaments corroding themselves against the quartz tube... it's a very gradual thing, and different kinds have different levels of black, so if it's just a little black, it's ok...