t5, pc, halide. same or different?

shawnkfl · 12/20/2007, 10:19 PM

is, say, 150 watts of pc lighting the same as 150 watts of t5 lighting, and 150 watts of halide lighting? i know the differences between them but to keep a reef, is a 150 watts, a 150 watts regardless of the type of lamp? so 450 watts for a 75 gallon, can it be any of the three to get the same keep the same inhabitants?

hahnmeister · 12/20/2007, 11:10 PM

I assume you are talking about efficiency w/ regards to output per watt, right? In that case, no, they are rather different. Halides lead the pack, and then T5s (depending on how blue you go, T5s can outdo halides), and then PC's and VHO's are only about 66% the efficiency of T5 or halide, and the easier bulb profiles of T5 and MH allow for much better reflectors over PC and VHO, so in the end T5s and MH's can easily be 2-3x as intense as PC's per watt.

garygb · 12/20/2007, 11:22 PM

Also, metal halides maintain their intensity deeper into the water column compared to pcs. t-5s penetrate more deeply than pc's, but not as deep as MH, from what I understand.

hahnmeister · 12/20/2007, 11:27 PM

the penetration into the water has to do with the reflector, as well as how spread out a light source is. Since a T5 is longer than a halide, it will penetrate deeper per watt than a halide actually. This is true of most forms of linear lighting.

garygb · 12/21/2007, 12:10 AM

Thanks Hahn, you definitely know more about this than I do. So for his question about 450 watts in a 75 gallon, he doesn't mention depth, but say it is 24 inches deep or less, could he keep anything he wants with t-5HO or MH (but not pc's because of their lack of penetration beyond 12 inches or so below the surface)? If he is going for a high light animal like sps or clams, would he be able to keep them all the way to the bottom of the tank assuming his is using a good fixture and appropriate configuration?

hahnmeister · 12/21/2007, 01:24 AM

It would take about 2-3x the wattage in PC's to match the output of T5s... the penetration would be the same even though the intensity may vary.... as in, the ratio of drop off from top to bottom in light intensity.

garygb · 12/21/2007, 11:17 AM

Thanks for the input.

shawnkfl · 12/21/2007, 08:26 PM

that's basically what my question was. so if i wanted to keep a clam. the watts per gallon doesn't really apply, depending on the lighting used? i have an odyssea PC fixture with 260 watts. (2) 65 watt daylight and (2) 65 watt actinics. the fixture was a great price for what i needed when i bought it and i was considering buying another one just like it. i just cannot justify spending $700.00 on MH right now. i mean, that's almost a mortgage payment to me. i have to think that 520 watts of PC lighting should be good enough to keep anything i want correct? granted, the light doesn't penetrate the water column as well as others, but wouldn't i still get enough light?

garygb · 12/21/2007, 09:35 PM

How far would the clam be from the bulbs and under water? The PAR drops off dramatically as the depth increases with PC's.

shawnkfl · 12/22/2007, 09:26 AM

well, my tank is 20" tall. i'll take up probably 2"-3" with sand and if i did get a clam, it would be on the rocks. so maybe 8"-12" from the surface.
the lights are about 4" above the surface. i could bring the clam up higher as well. at this point, i don't plan on keeping a clam. i'm really just trying to find out if i "could" keep one should i walk in to a LFS and find one that i just had to have. eventually i will go with MH lighting, but for now, i have to keep my PC and i can have either 260 watts or 520 watts of that. thanks to everyone helping with my questions. i very much appreciate it.

merry christmas!

12/20/2007, 10:19 PM	#1
shawnkfl Registered Member Join Date: Nov 2007 Location: Largo Posts: 227	t5, pc, halide. same or different? is, say, 150 watts of pc lighting the same as 150 watts of t5 lighting, and 150 watts of halide lighting? i know the differences between them but to keep a reef, is a 150 watts, a 150 watts regardless of the type of lamp? so 450 watts for a 75 gallon, can it be any of the three to get the same keep the same inhabitants?

12/20/2007, 11:10 PM	#2
hahnmeister Moved On Join Date: Sep 2005 Location: Brew City, WI Posts: 10,156	I assume you are talking about efficiency w/ regards to output per watt, right? In that case, no, they are rather different. Halides lead the pack, and then T5s (depending on how blue you go, T5s can outdo halides), and then PC's and VHO's are only about 66% the efficiency of T5 or halide, and the easier bulb profiles of T5 and MH allow for much better reflectors over PC and VHO, so in the end T5s and MH's can easily be 2-3x as intense as PC's per watt.

12/20/2007, 11:22 PM	#3
garygb Registered Member Join Date: Aug 2004 Location: los angeles Posts: 4,471	Also, metal halides maintain their intensity deeper into the water column compared to pcs. t-5s penetrate more deeply than pc's, but not as deep as MH, from what I understand.

12/20/2007, 11:27 PM	#4
hahnmeister Moved On Join Date: Sep 2005 Location: Brew City, WI Posts: 10,156	the penetration into the water has to do with the reflector, as well as how spread out a light source is. Since a T5 is longer than a halide, it will penetrate deeper per watt than a halide actually. This is true of most forms of linear lighting.

12/21/2007, 12:10 AM	#5
garygb Registered Member Join Date: Aug 2004 Location: los angeles Posts: 4,471	Thanks Hahn, you definitely know more about this than I do. So for his question about 450 watts in a 75 gallon, he doesn't mention depth, but say it is 24 inches deep or less, could he keep anything he wants with t-5HO or MH (but not pc's because of their lack of penetration beyond 12 inches or so below the surface)? If he is going for a high light animal like sps or clams, would he be able to keep them all the way to the bottom of the tank assuming his is using a good fixture and appropriate configuration?

12/21/2007, 01:24 AM	#6
hahnmeister Moved On Join Date: Sep 2005 Location: Brew City, WI Posts: 10,156	It would take about 2-3x the wattage in PC's to match the output of T5s... the penetration would be the same even though the intensity may vary.... as in, the ratio of drop off from top to bottom in light intensity.

12/21/2007, 11:17 AM	#7
garygb Registered Member Join Date: Aug 2004 Location: los angeles Posts: 4,471	Thanks for the input.

12/21/2007, 08:26 PM	#8
shawnkfl Registered Member Join Date: Nov 2007 Location: Largo Posts: 227	that's basically what my question was. so if i wanted to keep a clam. the watts per gallon doesn't really apply, depending on the lighting used? i have an odyssea PC fixture with 260 watts. (2) 65 watt daylight and (2) 65 watt actinics. the fixture was a great price for what i needed when i bought it and i was considering buying another one just like it. i just cannot justify spending $700.00 on MH right now. i mean, that's almost a mortgage payment to me. i have to think that 520 watts of PC lighting should be good enough to keep anything i want correct? granted, the light doesn't penetrate the water column as well as others, but wouldn't i still get enough light?

12/21/2007, 09:35 PM	#9
garygb Registered Member Join Date: Aug 2004 Location: los angeles Posts: 4,471	How far would the clam be from the bulbs and under water? The PAR drops off dramatically as the depth increases with PC's.

12/22/2007, 09:26 AM	#10
shawnkfl Registered Member Join Date: Nov 2007 Location: Largo Posts: 227	well, my tank is 20" tall. i'll take up probably 2"-3" with sand and if i did get a clam, it would be on the rocks. so maybe 8"-12" from the surface. the lights are about 4" above the surface. i could bring the clam up higher as well. at this point, i don't plan on keeping a clam. i'm really just trying to find out if i "could" keep one should i walk in to a LFS and find one that i just had to have. eventually i will go with MH lighting, but for now, i have to keep my PC and i can have either 260 watts or 520 watts of that. thanks to everyone helping with my questions. i very much appreciate it. merry christmas!