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Topic Review (Newest First)
Today 08:10 PM
candymancan Yes but the graph you showed im assuming you didn't make that one, still seems very biased towards PC lighting...

I guess it makes sense if you have no reflector lol but come on even the basic PC fixtures have metal reflectors. The one I have from Current its a duel 65w one. If you go back to page 22 a guy posted pics of his.. That's the one I have.. It doesn't have curved metal for each bulb so I can see how each bulb would wash the other out.. but its still a reflector and the sides are curved at least. I have thought about taking the reflector out myself and bending it in the middle to better reflect the light. I like those reflectors on that website you linked though.

But yea even with a crappy reflector or no reflector a PC light surely is better then any T8 light lol.. As an example I took an old T8 fixture you know those bulky ones with the white reflectors.. I gutted it of the the t8 stuff and I put a 65w PC ballast inside and I mounted the light directly inside the white reflector the t8 bulb used to sit in lol.. but 1 65w PC bulb is deff a lot stronger lighting then an 18W T8 lol. Its also better then my duel T5NO with a metal reflector .. My plants.. some of which are high light plants like Tiger Lotus and Red Combamba and red ludwigia and one I can never get the name right.. Lippphidurious or whatever its called lol.. They are all red/purple...

Ever since I replaced the duel T5NO's and that T8 (I had 4 lights over this tanks 2xt8 plant grow and the duel T5NO) with just this one PC light (6700/10k combo) my Red Ludwigia instead of being green with those 4 lights is now red.. and my Lipphidious plants instead of being only purple half way up the tank are now purple all the way near the bottom about 20 inches down (its a 27g hex about 25 inches tall)

So from my personal experience this single PC light using a white T8 lights reflector (heck 4 inches of the light isn't even in the reflector) is better then the 4 combined T8/T5NO lights I had. This pic is my ghetto PC in a T8 hood.. see the ends.. they aren't even in the reflector.. Plus the 10k on this light isn't exactly ideal for color spectrum... And yet look at my plants.. Since they are about 5-6 inches tall right now (I trimmed them).. According to your chart with my tank being 25 inches tall and my lights another 2-3 inches above that... subtract 6 inches.. my PAR should be like only 10 or so. Yet why are my medium/high light plants red ? I don't use CO2 either..


Sooo yea again like I said PAR is overrated... big time. That and your chart you linked is way off lol.. The one on this thread is more accurate if you go by PAR his chart with my 25 inch tall tank, lights 3 inches above minus the 6 inch growth of my plant my PAR with the PC light is about 34-40 which is around the medium light according to your chart and what he said.. Because if I went by your chart my PAR being at 10 trust me my plants in the pics would be green.. I have had them in really low light tanks and they just grow green.. But according to your char my part is really low light and yet they are very colorful .







Today 01:10 PM
jeffkrol
Quote:
Originally Posted by candymancan View Post
I still don't think this PAR is correct... If this were true then having 1 T8 light or a Power compact light in a 25 inch tall tank apparently doesn't matter they both are low light... lol AIn fact this graph shows a PC light is almost identical to a single T8 light and that deff cant be true.. I've held a T8 6700 and a PC 6700 together and the PC is nearly double the brightness in the tank height tank. In fact I had 2 T8's and 2 T5NO over my 27g hexagon and replaced those 4 lights with 1 Power compact and my plants are still red and purple..

This is a Joke because I have some pretty strong reds and purples in some of my medium/high light plants using my Power Compact lighting.. And whats is AHS PC ?? What does the AHS stand for ?

This graph is basically saying the par from 1 T5HO is almost 50 at 25 inches and a PC light is like 2 or 3 par at 25 inches.. HAHAH ok lol... Has anyone actually measured a PC light with a reflector... these NO REFLECTOR graph are very biased... Why are you comparing individual T5HO reflectors with T8's and T5NO or PC light with no reflectors or white back grounds..

I haven't seen a T5NO use a white background.. The ones I've seen use reflectors, and my PC lights have reflectors on them... what company sells a PC light with no reflector. I've searched google for HOURS i cant find one person who has done measurments on PC lights with reflectors.. So until then that graph you posted above.. lol..


PAR is another FAD like watts per gallon.. It isn't accurate when measured in the proper 400-700nm range. PAR only measures the ACTIVE radiation output of a light... Not the usefull radiation PUR... That can be used.. so this is exactly another WPG fad that i wish would just go away.... You can have 2 6700k bulbs and 2 Plant grow bulbs.. those plant grows will outgrow those 6700k yet how can that be if the PAR is the same ? Because PAR isn't measuring the usefull lighting.. omg.. this is giving me a headache


Also your chart you post Jeffkrol and the ones posted on this sticky.. The measurements are WAYYYY off.. The ones he posted for T5HO's using like 15 different fixtures.. the average PAR at 25 inches for TWO bulbs is around 40-56 PAR And his chart for the PC lights.. using 1 36 or 55w BULB for 25 inches the par is 23.. So using a duel fixture for 2 bulbs the par is around 46. That's about the same as most of the T5HO light fixtures soo according to these charts a PC light near identical to a T5HO.. just depends on the reflector your T5HO has... Yet according to your chart PC bulbs are almost like T8's...
AHS is AH supply:
http://ahsupply.com/

As to 1) PAR meter accuracy.. I've stated and shown numerous times the "inaccuracies" of most meters..w/ the exception of a Li-Cor
2) Yes PAR measures (assume a li-cor for now) all light from about 400-700nm and treats each equally, which is not "exactly" correct based on the PUR idea...but it is relatively close..

IN general think of a progression from worse to better..
visual is worse than watts which lumens which is worse than lux which is worse than PAR which is worse than PUR which is worse than ind. measurements per species based on spectrum and quantum efficiency of a light......

any "economic" PAR meter has a terrible bias against light in the 660nm range and will under-sample it. It will also over-sample green and ect. each band having a corresponding inaccuracy..The 'hope" is w/ a full spectrum light that it averages out........ An "assumption"...........

Obviously "precision and accuracy are not at a "research" level.. and errors occur..
None should be taken as "scripture"...



Red line is approx how a Li-Cor measures light.....


As a side note T8's are marginally less efficient than a T5.. As to PC.. ???
Quote:
a. T8 is 40% more efficient than T12.

b. T5 is 51% more efficient than T12.

Yet, T5 in this environment is only 9% more efficient than T8.
without measureing each ind. light in it's "real world" env. all you can do is make assumptions..

I hear what you are saying in the fact that one shouldn't rely on any one measurement.. but one needs a starting point......

Even PUR is inaccurate based on an individual plant species..Since that "green line" is actually taken from an "average plant" response.. meaning an overall based on who knows what species..
speaking of PUR apparently there is one even better.......
Quote:
PSR, can be defined as the amount of radiant energy that can be
converted into and stored as chemical energy, in the form of organic matter created through
photosynthesis. There exists an obvious relationship among these three quantities:
PSR < PUR <
PAR
Comparison of the extreme terms, PSR and PAR, leads to the concept of efficiency of utilization
of radiant energy entering the water, by the microalgae
http://www.biophotix.com/resources/P...-+20130214.pdf

good luck finding a PSR (or PUR) meter.. or a cheap way to measure it.......
Quote:
PAR has been defined as the amount of radiant energy, preferably expressed as quantum units, available
within the approximate
spectral range from 350 nm to 700 nm (Tyler, 1966).
This definition does not prejudge the usefulness of this energy for microalgae because all photons,
regardless of wavelength, must be counted. In order to be efficient in the photosynthetic process, these
photons must be absorbed by the algal pigments. Thus one can define the photosynthetically usable
radiation (PUR), as the fraction of such wavelength that it can be absorbed by the algae. PUR depends
upon the pigment composition of the algal population as well as on the spectral composition of the
submarine radiant energy.
Lastly, only a fraction of the absorbed energy is really used in the photosynthetic process. The
transformation of absorbed energy into chemical energy is carried out with variable yields. A quantum
yield, Φ, has been defined by plant physiologists as the number of CO2
molecules transformed (i.e., reduced to carbohydrate), per quantum absorbed, or the number of CO2
moles per Einstein absorbed
http://www.obs-vlfr.fr/LOV/OMT/fichi...rel_DSR_78.pdf
Do we really need to go to that level??
Today 06:43 AM
candymancan I still don't think this PAR is correct... If this were true then having 1 T8 light or a Power compact light in a 25 inch tall tank apparently doesn't matter they both are low light... lol AIn fact this graph shows a PC light is almost identical to a single T8 light and that deff cant be true.. I've held a T8 6700 and a PC 6700 together and the PC is nearly double the brightness in the tank height tank. In fact I had 2 T8's and 2 T5NO over my 27g hexagon and replaced those 4 lights with 1 Power compact and my plants are still red and purple..

This is a Joke because I have some pretty strong reds and purples in some of my medium/high light plants using my Power Compact lighting.. And whats is AHS PC ?? What does the AHS stand for ?

This graph is basically saying the par from 1 T5HO is almost 50 at 25 inches and a PC light is like 2 or 3 par at 25 inches.. HAHAH ok lol... Has anyone actually measured a PC light with a reflector... these NO REFLECTOR graph are very biased... Why are you comparing individual T5HO reflectors with T8's and T5NO or PC light with no reflectors or white back grounds..

I haven't seen a T5NO use a white background.. The ones I've seen use reflectors, and my PC lights have reflectors on them... what company sells a PC light with no reflector. I've searched google for HOURS i cant find one person who has done measurments on PC lights with reflectors.. So until then that graph you posted above.. lol..


PAR is another FAD like watts per gallon.. It isn't accurate when measured in the proper 400-700nm range. PAR only measures the ACTIVE radiation output of a light... Not the usefull radiation PUR... That can be used.. so this is exactly another WPG fad that i wish would just go away.... You can have 2 6700k bulbs and 2 Plant grow bulbs.. those plant grows will outgrow those 6700k yet how can that be if the PAR is the same ? Because PAR isn't measuring the usefull lighting.. omg.. this is giving me a headache


Also your chart you post Jeffkrol and the ones posted on this sticky.. The measurements are WAYYYY off.. The ones he posted for T5HO's using like 15 different fixtures.. the average PAR at 25 inches for TWO bulbs is around 40-56 PAR And his chart for the PC lights.. using 1 36 or 55w BULB for 25 inches the par is 23.. So using a duel fixture for 2 bulbs the par is around 46. That's about the same as most of the T5HO light fixtures soo according to these charts a PC light near identical to a T5HO.. just depends on the reflector your T5HO has... Yet according to your chart PC bulbs are almost like T8's...



11-21-2014 08:39 PM
drasan Thanks for the help.
11-21-2014 07:42 PM
jeffkrol
Quote:
Originally Posted by drasan View Post
I appreciate all of your research & explanations - However, i have no clue what it all means. I asked my son who is currently in college & he had no idea either. Is there a simple way for a person of normal intelligence to figure out if 2 T8 aqueon 15 watt 18" bulbs are enough for a low light planted 55 gallon tank. The lights are in the original hood. Please help, I'm 53 and don't feel like going back to school. LOL Thanks
sure.. you have 30W of T8's over 55gal.. Even w/out a PAR meter I can guarantee low light...

11-21-2014 06:28 PM
drasan I appreciate all of your research & explanations - However, i have no clue what it all means. I asked my son who is currently in college & he had no idea either. Is there a simple way for a person of normal intelligence to figure out if 2 T8 aqueon 15 watt 18" bulbs are enough for a low light planted 55 gallon tank. The lights are in the original hood. Please help, I'm 53 and don't feel like going back to school. LOL Thanks
10-25-2014 03:25 PM
IiScaPeJuNkiEiI About the par data for cfl lights in a dome fixture.. Is the measurement taken with a polished dome? Or a regular satin finished one? Need to know how the par is affected either way please. Thanks!
10-25-2014 09:27 AM
sprocketdiver Ok try again so lights set for 7 hours continuous now 3 catfish and new plants.
10-24-2014 02:32 AM
sprocketdiver Thanks for the reply, some photos of the set up, I'm having trouble with algae and my plants not really taking off,
It's economic complete substrate and 1-2 bubbles co2 a second into an inline diffuser reactor
Baby tears all but dead now, watercress is spindly and very unhealthy, only the Brahmi is doing ok,
10-21-2014 05:25 AM
Hoppy
Quote:
Originally Posted by sprocketdiver View Post
Hi. I'm concerned I don't know what I'm dealing with. I have a 15 gallon. It's taller than wide. I have my light suspended from the ceiling. Not sure what distance to hang it though. Measured from the substrate. It's a 4 bulb t5ho fixture. But the reflector is funny. Advice. The reflector has loads of dimples all over it. It's not smooth.
A 4 bulb T5HO light is very likely to need to a considerable distance above the substrate, or you will have much more light than you can easily live with. I would use just two bulbs at a time, and try it at about 24 inches from the substrate. That should give you something in the low to medium light range.
10-20-2014 09:13 PM
sprocketdiver Hi. I'm concerned I don't know what I'm dealing with. I have a 15 gallon. It's taller than wide. I have my light suspended from the ceiling. Not sure what distance to hang it though. Measured from the substrate. It's a 4 bulb t5ho fixture. But the reflector is funny. Advice. The reflector has loads of dimples all over it. It's not smooth.
07-06-2014 05:33 PM
Hoppy
Quote:
Originally Posted by plantbrain View Post
Hoppy,

I have a new Apogee light meter now. It's pretty well corrected for the T5's for PAR and the curve. Has a few more options. Has other corrective %'s for other bulb types.

FYI.........
Sorry, I haven't been monitoring this much, and I'm in the middle of moving to an apartment, so my aquarium activities are turned off for now. Once I get moved and settled in a bit, I will want to borrow that PAR meter for awhile. I will let you know.
07-06-2014 02:11 AM
rthomas529 How can a 26w cfl produce 50% of par as a 23w cfl?
06-17-2014 11:07 PM
mistuhmarc Hey Hoppy,

I'm planning on updating the light fixture on my parent's 30gallon tank to three clamp light CFL fixtures. Each fixture will have a 23w CFL in I think more than likely 8.5" diameter domes. Would this be sufficient as medium light for the tank? Thanks!
06-10-2014 05:27 PM
plantbrain Hoppy,

I have a new Apogee light meter now. It's pretty well corrected for the T5's for PAR and the curve. Has a few more options. Has other corrective %'s for other bulb types.

FYI.........
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