Lighting on 40 long

bikinibottom · 11-19-2012, 05:48 PM

I have a 48" 4-bulb Tek T5HO fixture from an old saltwater setup. I want to use it on a 40 long -- 48"l x 12"w x 16"d. I'd also like to keep plants that require "medium" light, and would like to avoid CO2 (which I understand can be done with PAR = 35-50). If I used only one 54W 6500k bulb in this fixture would that still be too much PAR to avoid using CO2? I saw the sticky thread on lights/PAR, and if the Tek calculated values can be taken at face value it looks like the PAR might be about right near the bottom of the tank, but might be closer to 75-80 at the surface of the water.

Anyone successfully running a setup with one bulb 54w T5HO bulb, or have any advice for me?

biogenetic40379 · 11-19-2012, 06:57 PM

i had one t5ho on my 55g, it was 18 inches from light to substrate, I had no problems with out co2. I should have been running co2, but i never got my solenoid to seal right. Just be prepared to read about par (which you seem to already have started) and be able to move the light up off the tank. You could ask around to rent a par meter too, someone in my city does it so i don't see why there wouldnt be on in the DC area.

bikinibottom · 11-19-2012, 07:15 PM

Thanks, Biogen... that's a good idea about borrowing a PAR meter. I have connections with some science folks at UMD so it shouldn't be that hard to get my hands on one.

bikinibottom · 11-19-2012, 07:31 PM

Hey, Biogen... were you able to grow plants that needed a "medium" level of light? I'm interested in planting things like swords and other things that need a moderate level of light.

**Hoppy** · 11-19-2012, 08:32 PM

Don't forget that most plants that "require" more than low light, really require CO2 before they do well. It is the combination of light and CO2 that gets those plants to grow well.

bikinibottom · 11-19-2012, 09:41 PM

thanks, hoppy. Any thoughts on a siesta regime to increase co2? My (limited) understanding is that the co2 level goes down to almost 0 after the first 5 hours the lights are on, and that shutting them off for several hours brings the co2 level back up significantly while the plants respire. In theory, this regime would provide a little more co2 for the plants. I'm wondering if anyone has any data on whether this works or not.

11-19-2012, 05:48 PM	#1
bikinibottom Algae Grower (View User Tanks) PTrader: (0/0%) Join Date: Nov 2012 Location: Washington DC Posts: 115	Lighting on 40 long I have a 48" 4-bulb Tek T5HO fixture from an old saltwater setup. I want to use it on a 40 long -- 48"l x 12"w x 16"d. I'd also like to keep plants that require "medium" light, and would like to avoid CO2 (which I understand can be done with PAR = 35-50). If I used only one 54W 6500k bulb in this fixture would that still be too much PAR to avoid using CO2? I saw the sticky thread on lights/PAR, and if the Tek calculated values can be taken at face value it looks like the PAR might be about right near the bottom of the tank, but might be closer to 75-80 at the surface of the water. Anyone successfully running a setup with one bulb 54w T5HO bulb, or have any advice for me? Last edited by bikinibottom; 11-19-2012 at 05:56 PM.. Reason: edited PAR rating @ surface of water

11-19-2012, 06:57 PM	#2
biogenetic40379 Planted Member (View User Tanks) PTrader: (2/100%) Join Date: Jan 2012 Location: Columbia, MO Posts: 272	i had one t5ho on my 55g, it was 18 inches from light to substrate, I had no problems with out co2. I should have been running co2, but i never got my solenoid to seal right. Just be prepared to read about par (which you seem to already have started) and be able to move the light up off the tank. You could ask around to rent a par meter too, someone in my city does it so i don't see why there wouldnt be on in the DC area. __________________ Check out my 15g Red cherry shrimp tank http://www.plantedtank.net/forums/ta...ml#post1684884 or my 33G Long http://www.plantedtank.net/forums/sh...d.php?t=197147

11-19-2012, 08:32 PM	#5
Hoppy Planted Tank Guru (View User Tanks) PTrader: (54/100%) Join Date: Dec 2005 Location: Sacramento, CA Posts: 17,215	Don't forget that most plants that "require" more than low light, really require CO2 before they do well. It is the combination of light and CO2 that gets those plants to grow well. __________________ Hoppy

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11-19-2012, 07:15 PM	#3
bikinibottom Algae Grower (View User Tanks) PTrader: (0/0%) Join Date: Nov 2012 Location: Washington DC Posts: 115	Thanks, Biogen... that's a good idea about borrowing a PAR meter. I have connections with some science folks at UMD so it shouldn't be that hard to get my hands on one.

11-19-2012, 07:31 PM	#4
bikinibottom Algae Grower (View User Tanks) PTrader: (0/0%) Join Date: Nov 2012 Location: Washington DC Posts: 115	Hey, Biogen... were you able to grow plants that needed a "medium" level of light? I'm interested in planting things like swords and other things that need a moderate level of light.

11-19-2012, 09:41 PM	#6
bikinibottom Algae Grower (View User Tanks) PTrader: (0/0%) Join Date: Nov 2012 Location: Washington DC Posts: 115	thanks, hoppy. Any thoughts on a siesta regime to increase co2? My (limited) understanding is that the co2 level goes down to almost 0 after the first 5 hours the lights are on, and that shutting them off for several hours brings the co2 level back up significantly while the plants respire. In theory, this regime would provide a little more co2 for the plants. I'm wondering if anyone has any data on whether this works or not.