My Mercury Vapor Lamps no Good..

Martin

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Mar 8, 2005
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hi

just want your opinion/help.

I have 2 80/125W MV lamps over my 85G. Now that should give me wattage enough, but alas... Growth is not what I had expected. The only reason I can find is the bulbs. They are only 4000K

Base E-27
Burn Position Universal
Color Rendering Index 42
Color Temperature 4000 K
Finish Bright White Standard
Initial Lumens 6300 lm
Life 29000 Hrs.
Watts 125W

apparently you cannot get bulbs with higher Kelvin.

The dont seem to do anything for my plants. Growth is almost at a halt.. almost.. I helped it grow by adding a mister, but compared to when I had 188W of T5/T8, the MV lamps are not the Dogs B******s.


Any good ideas?

1 option is to use Sodium bulbs instead.. but dunno if that's such a good idea?


Am considering going back to T5's....

Symbiot.
 

neil1973

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Dec 17, 2005
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Stirling, UK
Re: My Mercury Vapor Lamps no Good..

Hi Symbiot

I am also using 125w mv bulbs with the same specifiction as yours. I'm using 2 on a 120litre tank (80cm x 40cm x 50cm) so quite alot of light i guess. I get alot of pearling within an hour or two of the lights been on so i guess there is no problem with photosynthesis, and growth is fast.

These bulbs definightly don't put out as many lumens per watt as tubes or halides and think most of the light is in certain areas of the spectrum so i don't think you can compare them to the equivelant wattage of flourecents etc... So on a tank your size maybe more would help but i don't really know.

But like i say i've had good results with this light, all be it a lot of it!

cheers
Neil
 

Martin

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Re: My Mercury Vapor Lamps no Good..

neil1973 said:
Hi Symbiot

I am also using 125w mv bulbs with the same specifiction as yours. I'm using 2 on a 120litre tank (80cm x 40cm x 50cm) so quite alot of light i guess. I get alot of pearling within an hour or two of the lights been on so i guess there is no problem with photosynthesis, and growth is fast.

These bulbs definightly don't put out as many lumens per watt as tubes or halides and think most of the light is in certain areas of the spectrum so i don't think you can compare them to the equivelant wattage of flourecents etc... So on a tank your size maybe more would help but i don't really know.

But like i say i've had good results with this light, all be it a lot of it!

cheers
Neil


hmm... really...
Strange... Hows your growth? is it centered around where the bulbs hang? or is it all over the tank... I get _very_ little pearling.. and only after adding Co2mister....
 

neil1973

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Dec 17, 2005
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Stirling, UK
Re: My Mercury Vapor Lamps no Good..

Well my tank is small, if seen from the top the tank area is 80 x 40cm so each lamp only has to light an area of 40 x 40cm. The lamps are about 30cm above the water so lighting is pretty much even throughout the tank. Like i say i don't think you can make direct comparisons between these and other lights of the same wattage, but the watt per gallon thing is only meant to be a guide. That said in my case i must have somthing like 8wpg so i probably wont matter what sort of light it is!

I got these lights originally not on any suposed plant growing properties but because i wanted an open top tank with some house plants round it, they were much cheaper than halides and the actual units look fairly nice in the room.

Neil
 

neil1973

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Dec 17, 2005
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Stirling, UK
Re: My Mercury Vapor Lamps no Good..

Sorry forgot to mention. When i first set the tank up the lights had 80w bulbs in and at that stage i didn't get much pearling but i also didn't have the co2 and nutrients properly sorted. Recently i went away for about 10 days so couldn't fertilize the tank etc. so i put the 80w bulbs back in and reduced the photo period from 10 to 7 hours. This was done to try and slow things up while i was away and hopefully avoid too many nutrient problems. when i came back the plants had grown loads. Before i left i had put in alot of nutrients, both macros and trace.

I'm not going to try and draw any great conclusions from any of this, just letting you have my obsivations. Hope it can help.

cheers
neil
 

Tom Barr

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Jan 23, 2005
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Re: My Mercury Vapor Lamps no Good..

I'd suggest goign back to the T5's or else go with Metal halides.

I've used MH's and MV lights.
The MV bulbs we have here were very blue colored.

The CRI's are extremely low for MV's, this is asethetically unacceptable for me. Sodiums are sometimes a little better, but very yellow.

Change the base and the ballast and go with MH's or go to PC bulbs or T5's.

Those are the best options as far electrical cost. The initial cost might be more, but the PAR you get from the MH's/T5's/PC's with E ballast save you the $$$ in about a year or two.

If you limit anything and spend the most $$, do so with lighting.

Regards,
Tom Barr