PC's

Doomer · 07-18-2003, 08:22 PM

When PC's are new they are a good deal brighter than they'll be for the majority of their life. Anybody know how much intensity they loose in the first month or so ? Or maybe a graph that shows intensity vs. life ?

Thanks

**GDominy** · 07-18-2003, 08:49 PM

That all depends on the bulb. Most manufacturers will list the initial Lumens with the Average Lumens as seperate statistics for the bulb.

What kin dof bulbs are you trying to get the specs for?

**GDominy** · 07-18-2003, 08:56 PM

Just an example, the GE 55 Watt PC bulbs that we have been discussing recently have an initial Lumen count of 4800. After a month this should drop to about 4080 Lumens, an approximate drop of 15% of the initial brightness

Doomer · 07-18-2003, 09:38 PM

Mine came from AH Supply. Dunno the brand, it's not listed on the box and all I can see on the bulb itself is 55w 6700k.

Everyone seems to talk in terms of watts per gallon rather than lumens which I've always thought was kinda strange. A 55watt bulb will remain a 55watt bulb it's entire life but if light output changes, as it obviously does, then thinking in terms of watts seems like a dumb way to approach lighting for a planted tank.

When one says that 3 WPG is ideal for a planted tank, is that new watts or old watts ?

**GDominy** · 07-18-2003, 10:36 PM

A watt is merely a measure of power consumption, it is a poor indication of light usage for plants. Lumens are also a poor indicator of light usage for plants as it is simply an indication of the light visible to the human eye, it has nothing to do with the radiation that the plants utilize.

The Watt per gallon rule is a "ROUGH" indication only of how much light you are providing your plants. Its not an exact science, and it never will be.

I guess in short what I am trying to say is:

A watt is a watt is a watt

No matter how old it is, a watt of energy is still a watt of energy.

Doomer · 07-18-2003, 11:30 PM

Yes but what do plants care of watts.

My original point was that a 55 watt lamp is always a 55 watt lamp. When new, it gives off more light. I assume that it does not consume more than 55 watts when new therefore a new watt is not an old watt.

I ask this question occassionally but have never gotten a straight answer.

m.lemay · 07-18-2003, 11:58 PM

Quote:

Yes but what do plants care of watts.

Plants don't care much about lumens either...... or color temp. What they really want is light thats high in the red and blue spectrums. None of the above measurements indicate one iota as to the red/blue output of a given lamp.

Marcel

Doomer · 07-19-2003, 12:26 AM

Thanks m.lemay. Time to do a little research to see if I can dig up this info on the lamps I'm currently running.

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07-18-2003, 08:22 PM	#1
Doomer Planted Tank Obsessed (View User Tanks) PTrader: (0/0%) Join Date: Jan 2003 Location: The Boondocks Posts: 468	When PC's are new they are a good deal brighter than they'll be for the majority of their life. Anybody know how much intensity they loose in the first month or so ? Or maybe a graph that shows intensity vs. life ? Thanks

07-18-2003, 08:49 PM	#2
GDominy Planted Tank VIP (View User Tanks) PTrader: (0/0%) Join Date: Jul 2002 Location: Victoria,British Columbia, Canada Posts: 3,276	That all depends on the bulb. Most manufacturers will list the initial Lumens with the Average Lumens as seperate statistics for the bulb. What kin dof bulbs are you trying to get the specs for?

07-18-2003, 08:56 PM	#3
GDominy Planted Tank VIP (View User Tanks) PTrader: (0/0%) Join Date: Jul 2002 Location: Victoria,British Columbia, Canada Posts: 3,276	Just an example, the GE 55 Watt PC bulbs that we have been discussing recently have an initial Lumen count of 4800. After a month this should drop to about 4080 Lumens, an approximate drop of 15% of the initial brightness

07-18-2003, 09:38 PM	#4
Doomer Planted Tank Obsessed (View User Tanks) PTrader: (0/0%) Join Date: Jan 2003 Location: The Boondocks Posts: 468	Mine came from AH Supply. Dunno the brand, it's not listed on the box and all I can see on the bulb itself is 55w 6700k. Everyone seems to talk in terms of watts per gallon rather than lumens which I've always thought was kinda strange. A 55watt bulb will remain a 55watt bulb it's entire life but if light output changes, as it obviously does, then thinking in terms of watts seems like a dumb way to approach lighting for a planted tank. When one says that 3 WPG is ideal for a planted tank, is that new watts or old watts ?

07-18-2003, 10:36 PM	#5
GDominy Planted Tank VIP (View User Tanks) PTrader: (0/0%) Join Date: Jul 2002 Location: Victoria,British Columbia, Canada Posts: 3,276	A watt is merely a measure of power consumption, it is a poor indication of light usage for plants. Lumens are also a poor indicator of light usage for plants as it is simply an indication of the light visible to the human eye, it has nothing to do with the radiation that the plants utilize. The Watt per gallon rule is a "ROUGH" indication only of how much light you are providing your plants. Its not an exact science, and it never will be. I guess in short what I am trying to say is: A watt is a watt is a watt No matter how old it is, a watt of energy is still a watt of energy.

07-18-2003, 11:30 PM	#6
Doomer Planted Tank Obsessed (View User Tanks) PTrader: (0/0%) Join Date: Jan 2003 Location: The Boondocks Posts: 468	Yes but what do plants care of watts. My original point was that a 55 watt lamp is always a 55 watt lamp. When new, it gives off more light. I assume that it does not consume more than 55 watts when new therefore a new watt is not an old watt. I ask this question occassionally but have never gotten a straight answer.

07-19-2003, 12:26 AM	#8
Doomer Planted Tank Obsessed (View User Tanks) PTrader: (0/0%) Join Date: Jan 2003 Location: The Boondocks Posts: 468	Thanks m.lemay. Time to do a little research to see if I can dig up this info on the lamps I'm currently running.