confusion over color/temp or Kelvin rating of MH bulbs

[cracker]

I have MH lighting on several of my aquariums. There is a wide choice of color or spectrum of of light output. Not how much but the color. 65.00 K (kelvin) bulbs put out a yellow wavelenght !0,00K bulbs are more white and 20 k bulbs are blue in color output.

I don't see these choices with the MH grow lamps . I think around 65 k bulbs( puts out light in the yellow spectrum )are good for plant growth. All I see is full spectrum bulbs. But these must have some sort of specific color or at least a small range of color output . A bulb putting out light that covers the entire color spectrum, from red/ yellow to white/blue also! is this right? I need to replace some MH bulbs . I assume I just get these Full spectrum bulbs that match wattage and endcaps of the ballast? I will have to use all mh lighting for now and need suggestions on the best bulb to purchase. Thanks

[SukonmiSkunk]

A MH is ok to use for the whole grow... not really recommended for flowering but they do work and work well.. to change bulbs you need to change ballasts.. but its a HPS kit you need for best results for flowering...MH globes wont work in a hps ballast...well I think they do but you lose wattage.. and its not a great practice to mix the 2.

as for the best bulbs to use I use "sunmaster" globes. they are supposed to be closer to the sun specturm when flowering.. might be a gimik but they do seem to work well.. or a "son-t-agro plus" these bulbs put out a little more lumins (most of any globe according to my chart)... but isnt "spectrum adjusted" but they do work excellently.. and the whole "spectrum adjusted" thing could just be bullshit....

[cracker]

I agree the full spectrum claims are BULL! You can run low er watt bulbs in some cases. Here an interesting article on Diy ligh

 

http://www.icecapinc.com/rev1.htm

here Ya go this should work better

Edited July 1, 2006 by cracker

[WantDaChronic]

edit: didn't read the post right

[cracker]

Thanks for the suggestions for bulbs. I guees Ya'll call them globes down there . But getting way ahead of myself here I don't even know if this MH fixture has Mogul or double end caps!

[Luke Skywalker]

Colour temp is only a rough guestimate anyway, showing the approximate comparison between the light source being measured and the same colour a black body makes when heated to that temp in degrees kelvin.

 

So whilst a 10,000K bulb is about the same colour as a 10,000k black body, the bulb may well put out a substantial component of spectrum in other areas.

 

Kelvin ratings aren't really relevant for growing, although they do give you an idea about what kind of colour you can expect. Try and get something showing the full spectrum of the bulb in question. PAR watts is the ultimate in determining how effective a bulb is to grow under, but searching out that particular gem of information may not be as easy as you think.

 

And yeah, MH can grow in flower and growth cycles, but typically aren't as efficient as HPS lamps.

[cracker]

Thanks Luke! The PAR watts is what I'm looking for and understood. Getting specs on bulbs is a pita for sure. Call the manufacturer and they don't even know!

May the force be with You!

[nitram]

Hi cracker,

 

There is a wide choice of color or spectrum of of light output. Not how much but the color.

 

 

This is a reasonable chart with colour/Kelvin scale & light. I found it useful to reference.

 

 

PS/ You must be looking after those fish/aquaplants.

[cracker]

What I don't get is with all the differant color bulbs available for MH fixtures why do you need the HPS fixtures ? Is there something about the ballast or gasses used in MH lighting that can't match the color of HPS fixtures?