can you have to much light

hixy · 02-06-2004, 04:39 PM

ive been round the local lfs shops in my area and one of them is selling a twin 250 watt metal halide light .would this be over the top for my 4x2x18 aquarium as its 500 watt output, he only wants £200 for it

hixy

Rolo · 02-06-2004, 05:17 PM

If you want to grow a tank of algae, thats the lighting I would use. Thats about 5.6 WPG in MH! Assumning your tank is ~ 90 gallons. You will mostly be battling algae and nutrient problems all the time with that amount.

For larger tanks, about ~2.5 wpg is a nice and balance amount of light.

hixy · 02-06-2004, 08:08 PM

thanks alot mate,another quick maybe silly question is 70 of mh light the same as 70 watt of floresence

thanks

hixy

Wasserpest · 02-06-2004, 09:03 PM

Fluorescent and MH light have a similar efficiency, so the watt output is comparable. 500 Watts is a lot of light and a lot of heat.

Remembering all the algae stories of MH owners, I wouldn't...

**GDominy** · 02-06-2004, 09:44 PM

Actually... from personal experience.. thats not too bad.

If you raise the fixture away from the top of the tank by say.. 8-12" you will have fantastic lighting for a planted tank.
There is absolutely no reason why you cant use MH lighting over a planted tank, you just have to be aware of a few things like Heat, intensity etc.. some plants may react a bit to the intense non-diffused light but they will adapt.

Rolo · 02-06-2004, 10:45 PM

Well yeah, if you raise the height of the lighting then it will be less a problem. I think that would be nescessary for HM becuase of the heat. So in fact it could work, but trial and error will need to find the proper height; and 500W is still alot.

mario · 02-06-2004, 10:56 PM

If you have two hundred pounds to spare, go for it. Supend them well over your tank and create one of those beautiful open-topped planted tanks.

**GDominy** · 02-06-2004, 10:58 PM

Mario's got the idea ;-) I've been thinking I might just do this for my 135 Gallon :-) Set up 2-3 250 watt pendants over it... hmmm...

putty · 02-06-2004, 11:10 PM

Open top tanks are beautiful, with plants growng out of them etc. I love watching fish from above the surface of the water. When I redo my tanks I am making them both open top.

Wasserpest · 02-06-2004, 11:31 PM

Beautiful, yes. But evaporation, and condensation on the cold walls of your sweet home need to be considered...

**GDominy** · 02-08-2004, 03:47 AM

wasserpest.... none of my tanks have lids exactly.. I have 3 windows open at all time. I dont need to heat my place either because I have enough lights and computer equipment running it keeps everything toasty.. lol

02-06-2004, 05:17 PM	#2
Rolo Wannabe Guru (View User Tanks) PTrader: (4/100%) Join Date: Dec 2003 Location: Twin Cities, Minnesota Posts: 1,716	If you want to grow a tank of algae, thats the lighting I would use. Thats about 5.6 WPG in MH! Assumning your tank is ~ 90 gallons. You will mostly be battling algae and nutrient problems all the time with that amount. For larger tanks, about ~2.5 wpg is a nice and balance amount of light. __________________

02-06-2004, 09:03 PM	#4
Wasserpest Are these real? (View User Tanks) PTrader: (140/100%) Join Date: Jun 2003 Location: Monterey, CA Posts: 14,648	Fluorescent and MH light have a similar efficiency, so the watt output is comparable. 500 Watts is a lot of light and a lot of heat. Remembering all the algae stories of MH owners, I wouldn't... __________________ All my tanks Autodosing Water Change Temperature Monitoring Cheap Filter The Wasser-Controller

02-06-2004, 09:44 PM	#5
GDominy Planted Tank VIP (View User Tanks) PTrader: (0/0%) Join Date: Jul 2002 Location: Victoria,British Columbia, Canada Posts: 3,276	Actually... from personal experience.. thats not too bad. If you raise the fixture away from the top of the tank by say.. 8-12" you will have fantastic lighting for a planted tank. There is absolutely no reason why you cant use MH lighting over a planted tank, you just have to be aware of a few things like Heat, intensity etc.. some plants may react a bit to the intense non-diffused light but they will adapt. __________________ Gareth

02-06-2004, 10:45 PM	#6
Rolo Wannabe Guru (View User Tanks) PTrader: (4/100%) Join Date: Dec 2003 Location: Twin Cities, Minnesota Posts: 1,716	Well yeah, if you raise the height of the lighting then it will be less a problem. I think that would be nescessary for HM becuase of the heat. So in fact it could work, but trial and error will need to find the proper height; and 500W is still alot. __________________

02-06-2004, 10:58 PM	#8
GDominy Planted Tank VIP (View User Tanks) PTrader: (0/0%) Join Date: Jul 2002 Location: Victoria,British Columbia, Canada Posts: 3,276	Mario's got the idea ;-) I've been thinking I might just do this for my 135 Gallon :-) Set up 2-3 250 watt pendants over it... hmmm... __________________ Gareth

02-06-2004, 04:39 PM	#1
hixy Algae Grower (View User Tanks) PTrader: (0/0%) Join Date: Dec 2003 Location: birmingham england Posts: 133	ive been round the local lfs shops in my area and one of them is selling a twin 250 watt metal halide light .would this be over the top for my 4x2x18 aquarium as its 500 watt output, he only wants £200 for it hixy

02-06-2004, 08:08 PM	#3
hixy Algae Grower (View User Tanks) PTrader: (0/0%) Join Date: Dec 2003 Location: birmingham england Posts: 133	thanks alot mate,another quick maybe silly question is 70 of mh light the same as 70 watt of floresence thanks hixy

02-06-2004, 10:56 PM	#7
mario Planted Member (View User Tanks) PTrader: (0/0%) Join Date: Feb 2003 Location: Boston, MA, USA Posts: 287	If you have two hundred pounds to spare, go for it. Supend them well over your tank and create one of those beautiful open-topped planted tanks.

02-06-2004, 11:10 PM	#9
putty Planted Tank Enthusiast (View User Tanks) PTrader: (0/0%) Join Date: Nov 2003 Location: Vancouver, B.C. Posts: 666	Open top tanks are beautiful, with plants growng out of them etc. I love watching fish from above the surface of the water. When I redo my tanks I am making them both open top. __________________ got CO2?

02-06-2004, 11:31 PM	#10
Wasserpest Are these real? (View User Tanks) PTrader: (140/100%) Join Date: Jun 2003 Location: Monterey, CA Posts: 14,648	Beautiful, yes. But evaporation, and condensation on the cold walls of your sweet home need to be considered... __________________ All my tanks Autodosing Water Change Temperature Monitoring Cheap Filter The Wasser-Controller

02-08-2004, 03:47 AM	#11
GDominy Planted Tank VIP (View User Tanks) PTrader: (0/0%) Join Date: Jul 2002 Location: Victoria,British Columbia, Canada Posts: 3,276	wasserpest.... none of my tanks have lids exactly.. I have 3 windows open at all time. I dont need to heat my place either because I have enough lights and computer equipment running it keeps everything toasty.. lol __________________ Gareth

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