T5 and PAR issues

Turkey8it · 05/05/2016, 10:14 AM

Hi all, new here...so much great info! I'm setting up a new research experimental tank system using 4 x 55W T5 HO actinic, daylight, and blue (48") lighting that's approximately 16" above the top of about 16 2.5 gal glass tanks. Typically for research, we should have PAR readings of about 300 umol/m2/sec, but I'm only getting about 90-100 with that set-up. Even if I bring the light fixtures closer to the tanks, I can only really ever get about 200 PAR at coral level. Other researchers claim they're getting ~300 PAR at coral level with no problem using the same system. Can anyone help explain why my light is scattering so much before it gets to the water? Measurement of PAR right at the light is about 500 umol/m2/sec. Thanks for any advice!

Reef Frog · 05/05/2016, 10:38 AM

A few possibilities:

Particulate matter in the water is shading or scattering the light

Are the tubes new?

Does your fixture have high quality reflectors?

An acrylic or glass top will reduce PAR somewhat, especially if condensation or salt crust is present.

Wild guess bc I'm not an expert on lighting hardware: your fixture or tubes may have a defect that is keeping them from their full potential. I would measure my colleagues system with the same meter you're using now. The results may provide a clue.

Good luck.

Turkey8it · 05/05/2016, 11:25 AM

The acrylic covers were already removed. Water is clear (new, flow through system). My guess is probably the lack of high quality reflectors. Will try that route next! Thank you!

Reef Frog · 05/05/2016, 11:38 AM

You're welcome.

For what it's worth, several T5 fixture manufacturers claim that their reflectors provide 200% - 300% more light than a T5 tube tested without one.

Bagabaga · 05/05/2016, 03:32 PM

Bulb manufacturers also vary greatly and quality bulbs will provide a better par. And you say it's an ho unit but didn't provide a brand name or if the ballast are driving the bulbs to be ho. Any more details on your ballasts or fixture manufacturer?

Turkey8it · 05/17/2016, 01:27 PM

We are using HO T5 actinic, daylight, and blue (it's an 6 bulb fixture; ATI1137 ATI 54 W. CORAL PLUS). Light fixtures are 48" Aquaticlife 6 bulb T5 fixtures.

Toby_Kourtney · 05/17/2016, 01:42 PM

If you replace the actinic with another blue plus or coral plus it will bump your par up significantly. Aquaticlife fixtures are mid range fixtures so they should be putting out a decent amount of par.

05/05/2016, 10:14 AM	#1
Turkey8it Registered Member Join Date: May 2016 Posts: 3	T5 and PAR issues Hi all, new here...so much great info! I'm setting up a new research experimental tank system using 4 x 55W T5 HO actinic, daylight, and blue (48") lighting that's approximately 16" above the top of about 16 2.5 gal glass tanks. Typically for research, we should have PAR readings of about 300 umol/m2/sec, but I'm only getting about 90-100 with that set-up. Even if I bring the light fixtures closer to the tanks, I can only really ever get about 200 PAR at coral level. Other researchers claim they're getting ~300 PAR at coral level with no problem using the same system. Can anyone help explain why my light is scattering so much before it gets to the water? Measurement of PAR right at the light is about 500 umol/m2/sec. Thanks for any advice!

05/05/2016, 10:38 AM	#2
Reef Frog Registered Member Join Date: Feb 2013 Location: Maryland Posts: 3,121	A few possibilities: Particulate matter in the water is shading or scattering the light Are the tubes new? Does your fixture have high quality reflectors? An acrylic or glass top will reduce PAR somewhat, especially if condensation or salt crust is present. Wild guess bc I'm not an expert on lighting hardware: your fixture or tubes may have a defect that is keeping them from their full potential. I would measure my colleagues system with the same meter you're using now. The results may provide a clue. Good luck.

05/05/2016, 11:25 AM	#3
Turkey8it Registered Member Join Date: May 2016 Posts: 3	The acrylic covers were already removed. Water is clear (new, flow through system). My guess is probably the lack of high quality reflectors. Will try that route next! Thank you!

05/05/2016, 11:38 AM	#4
Reef Frog Registered Member Join Date: Feb 2013 Location: Maryland Posts: 3,121	You're welcome. For what it's worth, several T5 fixture manufacturers claim that their reflectors provide 200% - 300% more light than a T5 tube tested without one.

05/05/2016, 03:32 PM	#5
Bagabaga Registered Member Join Date: Jan 2015 Posts: 517	Bulb manufacturers also vary greatly and quality bulbs will provide a better par. And you say it's an ho unit but didn't provide a brand name or if the ballast are driving the bulbs to be ho. Any more details on your ballasts or fixture manufacturer?

05/17/2016, 01:27 PM	#6
Turkey8it Registered Member Join Date: May 2016 Posts: 3	We are using HO T5 actinic, daylight, and blue (it's an 6 bulb fixture; ATI1137 ATI 54 W. CORAL PLUS). Light fixtures are 48" Aquaticlife 6 bulb T5 fixtures.

05/17/2016, 01:42 PM	#7
Toby_Kourtney Registered Member Join Date: Feb 2014 Location: Minot ND Posts: 255	If you replace the actinic with another blue plus or coral plus it will bump your par up significantly. Aquaticlife fixtures are mid range fixtures so they should be putting out a decent amount of par.