Watts per gallon vs. Par

scionreefing · 01/15/2012, 10:22 AM

I have a buddy that's growing very nice acros and other corals. Thing is he is running 2 250 halides and like 6 pc packed over a 90. Then he states that all the big corals growers have 15 to 18 watts per gallon. I know I know whatever works best for someone may not work for everybody. But am I missing something I though the whole watt per gallon thing is useless these days.

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dsmhero · 01/15/2012, 10:34 AM

What is your question?

Watts/gallon has nothing to do with par, period.

rtparty · 01/15/2012, 10:59 AM

Watts per gallon is useless. Go put 18 watts per gallon of LED over your tank and watch everything die.

Your buddys tank is overlit IMO. I am not arguing withh results but he could pull 4 of the PCs and be fine still. The 6 PCs are actually doing very little for him. He is lucky if they even add 100-150 PAR. He would be better off to dump all 6 and use more efficient T5s for supplements.

dsmhero · 01/15/2012, 11:05 AM

^ ....4000th post!

scionreefing · 01/15/2012, 11:45 AM

Quote:

Originally Posted by dsmhero

^ ....4000th post!

Yeah I bet. I just wanted to make sure I'm not missing anything.
I run 6 t5s over my tank and my acros do fine.
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scionreefing · 01/15/2012, 11:46 AM

Quote:

Originally Posted by rtparty

Watts per gallon is useless. Go put 18 watts per gallon of LED over your tank and watch everything die.

Your buddys tank is overlit IMO. I am not arguing withh results but he could pull 4 of the PCs and be fine still. The 6 PCs are actually doing very little for him. He is lucky if they even add 100-150 PAR. He would be better off to dump all 6 and use more efficient T5s for supplements.

I agree he also told me t5s would do it. I laughed to myself.

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Woodchuck12 · 01/15/2012, 12:50 PM

Not to get this thread off topic, but what is PAR?

Thank, Charlie

Mark Bianco · 01/15/2012, 02:00 PM

Par is the measurements of light A Par meter will indicate how much is being distrubuted at a given point...

Reefers Digest · 01/15/2012, 02:37 PM

PAR is actually a measure of Photosynthetically Available (Active) Radiation... It's a measure of usable light for photosynthesis at any point in your tank. It only takes into account the energy level of photons that may be used in photosynthesis (by chlorophyll and accessory pigments) and accounts for the amount hitting a m^2 in a second (measured in micromoles).

Watts per gallon has no compensation for how efficient the lighting is nor its spectrum.

Hope this helps.

rtparty · 01/15/2012, 02:41 PM

Quote:

Originally Posted by Woodchuck12

Not to get this thread off topic, but what is PAR?

Thank, Charlie

PAR stands for Photosynthetic Active Radiation or in simple terms, "how much light is REALLY there." Brightness and PAR are two different things. The human eye finds "white" light to be very bright but in reality PAR could be very low. Our eyes are just tricked into thinking there is a lot of light.

There is also a thing called PUR, Photosynthetic Usable Radiation. It measures how much PAR is actually usable for the corals. It is a MUCH better measurement for us but almost impossible to create a "standard" that we can all use.

Different light sources put out different amounts of PUR and all corals are different. You could take frags from the same mother colony and place them in two different tanks. Depending on the chemistry of each tank, the PUR can change for each coral even though they are from the same mother colony. (This is what I understand at least and my knowledge is pretty limited when it comes to PUR.)

There is a professor at Penn State that is VERY big into the PUR scene but I don't remember his name. Adam Blundell, a local marine biologist and hobbyist, told me to look him up one day and send him an e-mail. Unfortunately, I never got around to it all.

Edit - Reefers Digest beat me to it. Very good summary.

01/15/2012, 10:22 AM	#1
scionreefing Moved On Join Date: Apr 2010 Posts: 344	Watts per gallon vs. Par I have a buddy that's growing very nice acros and other corals. Thing is he is running 2 250 halides and like 6 pc packed over a 90. Then he states that all the big corals growers have 15 to 18 watts per gallon. I know I know whatever works best for someone may not work for everybody. But am I missing something I though the whole watt per gallon thing is useless these days. Raffle grabber

01/15/2012, 10:59 AM	#3
rtparty Raise The Reef! Join Date: Oct 2008 Location: Utah Posts: 7,404	Watts per gallon is useless. Go put 18 watts per gallon of LED over your tank and watch everything die. Your buddys tank is overlit IMO. I am not arguing withh results but he could pull 4 of the PCs and be fine still. The 6 PCs are actually doing very little for him. He is lucky if they even add 100-150 PAR. He would be better off to dump all 6 and use more efficient T5s for supplements. __________________ Ryan Click on my user name and check out my homepage! Current Tank Info: 50g Cadlights/Giesemann Spectra (250w Radium, 2 ATI Blue Plus, 2 ATI Actinic)/2 x Vortech MP10wQD/Skimz SN123/Eheim Compact 3000+

01/15/2012, 10:34 AM	#2
dsmhero Registered Member Join Date: Jun 2010 Location: Montana Posts: 232	What is your question? Watts/gallon has nothing to do with par, period.

01/15/2012, 11:05 AM	#4
dsmhero Registered Member Join Date: Jun 2010 Location: Montana Posts: 232	^ ....4000th post!

01/15/2012, 12:50 PM	#7
Woodchuck12 Registered Member Join Date: Oct 2011 Location: Nebraska Posts: 245	Not to get this thread off topic, but what is PAR? Thank, Charlie

01/15/2012, 02:00 PM	#8
Mark Bianco In Memoriam Join Date: Nov 2011 Location: Infinity and Beyond Posts: 2,445	Par is the measurements of light A Par meter will indicate how much is being distrubuted at a given point...

01/15/2012, 02:37 PM	#9
Reefers Digest Registered Member Join Date: Mar 2011 Location: Port Credit, Ontario Posts: 111	PAR is actually a measure of Photosynthetically Available (Active) Radiation... It's a measure of usable light for photosynthesis at any point in your tank. It only takes into account the energy level of photons that may be used in photosynthesis (by chlorophyll and accessory pigments) and accounts for the amount hitting a m^2 in a second (measured in micromoles). Watts per gallon has no compensation for how efficient the lighting is nor its spectrum. Hope this helps.