# mercury vapour



## Robthekop (8 Sep 2010)

Just setting up a 5' x 15"x 24" planted tank in my fishroom (converted garage) , I'm new to this level of planted tank i.e. CO2 and high end lighting and substrate etc, my local fish shop owner has kindly given me free of charge a pair of Bioplast black pendant mercury vapour lighting plus a  CO2 regulator and solenoid valve, presumably from what was once his planted stock section.  

I have set up the MV lighting and have noticed it gets as hot as the Metal Halide light over my reef tank and the light is also somewhat yellowish. Few questions, how close to the surface of tank do the pendants drop? would I be better off ditching them for T5 compacts or are these lights worth running with still?, do I have to supplement it with a beauty/gro-lux lighting to enhance colour within the tank, are there alternative replacement bulbs out there?


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## dw1305 (9 Sep 2010)

Hi all,
Mercury Vapour lamps (all discharge lamps in  fact) run very hot, because the light is emitted from an inner fused quartz glass capsule in which the metal is ionized at very high temperatures to create an arc between the electrodes. The emission spectra from the mercury are heavily biased to the UV and blue end of the spectrum, so the yellow colours must be caused by the phosphors on lamp coating. 

They must also be very old stock, as MV lamps are quite difficult to get now having been superseded by MH (mercury with a halide impurity added) or high pressure sodium lamps. The EU has banned the use of all MV lighting from 2015.

They will be magnetically ballasted or may possibly be self-ballasted & have a tungsten filament in the bulb? (MBTF or MBSE on the lamp). If they are self-ballasted they run even hotter and have an increased risk of catastrophic failure if moisture gets on the lamp.

You my be able to replace the mercury vapour bulb with a compact fluorescent growlight that will use the same ballast.

cheers Darrel


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## ghostsword (9 Sep 2010)

@ dw1305


> You my be able to replace the mercury vapour bulb with a compact fluorescent growlight that will use the same ballast



Now this is something that I need to look at as well. I got a old arcadia classic with a vapour lamp, and would like to replace it with a CFL or grow light. 

Should be able to do a rewire as the some hydrophonic CLF's are self balast, right?


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## Robthekop (9 Sep 2010)

Thanks Darrel

Here is a pic of them, as I said there genuine aquatic ones from Bioplast with an Osram HQL 125w bulb in each.


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## dw1305 (10 Sep 2010)

Hi all,
They look very smart in a "retro" style. You can still get the lamps for these, in fact Dennerle sell exactly that lamp and it quotes the light colour as 3200K, so they would appear quite yellow. I think MV's were a lot more popular in mainland Europe, rather then the UK

They are magnetically ballasted, so replacing them with a CFL would be problematic, but you can almost certainly get a much more efficient 125W metal halide (in a range of colour temperatures) as a direct replacement.  <http://www.cp-lighting.co.uk/Lamps/125W-MBF-U-Deluxe-Comfort>.

cheers Darrel


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## Robthekop (10 Sep 2010)

Thanks DW, when you say direct replacement do you mean simply swap the MV bulb in the unit for a 125W MH? thanks for the link are these bulbs suitable for plant growth i.e. spevtrum etc? excuse my ignorance on the subject, do they need lowering down a bit?. Remember seeing lots of pics with these lights years back but despite some serious googling I can't find any pics of them in use.


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## dw1305 (11 Sep 2010)

Hi all,


> direct replacement do you mean simply swap the MV bulb in the unit for a 125W MH?


 Yes I do, the MH lamps replace either high pressure sodium (HPS) or MV lamps and use the same control gear as either HPS or MV. 
You need a 125W MV replacement. There should be some threads with suitable MH lamps, again colour temperature is largely a matter of personal choice, 2500K is Yellow and 20,000K is actinic blue but plants can use some of the spectra produced by all lamps in this range of Kelvin values, again best to have a search through the threads for details on PAR.   

Looking at the luminaires they need to be quite high to get the light spread over the tank, the 2 factors you need to bear in mind are that the intensity of the light falls off as a square of the distance from the lamp, and that MV lamps show a lot of lamp lumen depreciation (>50%) over their lifetime, so new lamps may be a lot brighter.

cheers Darrel


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## Robthekop (22 Sep 2010)

Thanks Darrel, I've emailed CP Lighting twice without reply, I'll call them when I've got the tank a bit more set up.


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## dw1305 (23 Sep 2010)

Hi all, 
Robthekop wrote 





> I've emailed CP Lighting twice without reply


Sorry about that, I don't know anything about CP lighting, but I thought they would probably be OK, because the web site looked professional. 

If they don't get back to you you could try contacting *BLT* <http://www.bltdirect.com/>, *Lightbulbs direct* <http://www.lightbulbs-direct.com/> or *Lampspecs *<http://www.lampspecs.co.uk/>, they often have, or can get lamps, that aren't on the web-site. 

cheers Darrel


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## Robthekop (10 Sep 2011)

These MV units have a switch to change to 80w really concerned over the ruinning costs of them so still looking for alternative bulbs for them.

Would these be out of the question with the balasts:

http://www.amazon.co.uk/Daylight-Energy ... B004V8G7GS


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