whats the difference in mh bulbs?

[kane420x]

hey all i was ardering some new mh bulbs and cant figure out all the difference with the bulbs. I need 400 watts but what does reduced envelope mean?

also what is the differenc ebetween this one for 10 bucks

• Brand : Plusrite
• Part No. : 1042
• UPC : 844366010422
• Wattage : 400 Watt
• ANSI Code : M59
• Base Type : Mogul (EX39)
• Bulb Shape : BT37-P
• Color Temp. (Kelvin) : 4200K

• CRI : 65
• Length (M.O.L.) : 11.5 in.
• Fixture Type : Open or Enclosed
• Life Hours : 20,000
• Lumens (Initial) : 40,000
• Burn Position : Base Up
• Case Quantity : 12
• Order Code : MP400/BT37/BU/4K

and this one for 28

• Brand : Sylvania
• Family : Super Metalarc
• Part No. : 64450
• UPC : 10046135644501
• Wattage : 400 Watt
• ANSI Code : M59/S *
• Base Type : Mogul (E39)
• Bulb Shape : BT37
• Color Temp. (Kelvin) : 4000K

• CRI : 65
• Diameter : 4.6 in.
• Length (M.O.L.) : 11.5 in.
• Protected : No
• Fixture Type : Open or Enclosed (Restricted Position)
• Life Hours : 20,000
• Lumens (Initial) : 42,000
• Burn Position : Base Up

and what does unprotected arc tube and protected arc tube mean?

thanks

 

[kane420x]

come on i know one of the super smart people on here has to know, i want to order some new bulbs and cant decide on which one.

 

[fabfun]

those appear to be only for vertical position and the second bulb has 2000 more lumens

 

[volcanoOFhistory]

The arc tube is where the electricity reacts with whatever the heck is in mh bulds to make light. I also notice that there is a kelvin difference between the two.

 

[bobhamm]

the arc tube is the long cylinder inside the bulb. It is pressurized and can rupture(explode) unprotected means ther is nothing between the arc cylinder and the outside glass of the bulb. If you have a hood with glass in it, this is the kind of bulb you can use, if your bulb is in an open reflector dont use it. A protected arc tube means there is something(can be more glass, can be a wire) around the inside cylinder to contain the rupture, you can use this in a reflector that doesn't have glass (open fixture).

Base up means use this bulb pointed down, in other words, if you have a standard reflector where the bulb is horizontal, dont use this type, you would want a universal position or a horizontal position bulb. You could use the base up horizontally, however you shorten the life(sometimes drastically) and possibly increase the chance of your bulb exploding(not absolutely positive about that, but I think so)

 

[bobhamm]

PS: the 200k diff in the kelvin really doesnt matter, most bulbs will drift in there kelvin ratings over time anyway

You are ebst off finding a universal position bulb, rated for an open fixture(unless your hood is enclosed in glass) "/O" is usually in the description for open rated, /E means use in an enclosed hood

 

[Spanishfly]

A protected arc tube means there is something(can be more glass, can be a wire) around the inside cylinder to contain the rupture, you can use this in a reflector that doesn't have glass (open fixture).

Often a quite insubstantial piece of wire.

 

[bobhamm]

Often a quite insubstantial piece of wire.

true, just because its "Open rated" doesnt mean it can't go blooey! as for the wire, mostly I was thinking about CMH bulbs, sometimes have those because for some reason they don't 'splode so big, its all relative though

 

[Dwezelitsame]

i runa hortilux 250w hps, and a phillips cmh250w. My tent looks entirely different like a show room, like day light on a clear day.I think im going to like the cmh already. I got rid of old mh up as spare, it was used for almost two years. I had been useing the eye hortilux for a while now. I replaced mh with cmh i only used it a couple months on my last grow. Never used it for a full grow yet so i can compare differences. I also cleaned the glass in cool tub and th heat controlled reflector. if its been a while since you cleaned yours especially if you mist. You would be amazed to see the difference in cleaned bulb and rflector glass if you have one.

 

[bobhamm]

yeah I have acou[ple of easy ryders under a cmh(after first under cfls) and they have just gone crazy after switching to the cmh

 

[kane420x]

can i use a cmh in a homemade ballast i use for mh or do i need a new one or can i use my hps ballast for it?

 

[bobhamm]

150 watt cmh requires mh ballast,250 and 400 watt cmh will run only on a hps ballast

 

[Spanishfly]

can i use a cmh in a homemade ballast i use for mh or do i need a new one or can i use my hps ballast for it?

CMH will only run with a magnetic HPS ballast, we are told. But the only difference between MH and HPS ballasts is that the HPS ballasts come wired to an ignitor. A magnetic ballast is just a huge inductance, so no reason why you can´t wind one yourself.