link for lux recommendations
- Thread starter Jpharr
- Start date
Thanks wiskey, great informative thread. By the way, I see that basically 250-300 par is good, but what about the photoperiod. Do you leave it at that for 5 hours like weatherman or do you keep it higher. Just curious. Planning to continue getting more and more serious about SPS.
Wiskey
New member
I am accually having some issues with a couple of corals lighting up, so I have dropped the photoperiod to 4.5 hours, the problem with my tank being only 16 inches deep is I can't really hide sensitave corals out of the light. What I am looking for is the lowest commen light demonater right now, I am also experementing with heaver feeding to give the coral more DOC.
I think my skimmer is running wet intermentantly, and I think that is causing some issues as well. (my tank is bb) (MR-2 order in the works)
My current light caculates out to at least 220 par in all areas, but some areas are higher than 350 but I can't mount the lights any higher.
I don't think a LUX meater really converts to par quite that easy though, I would definitally reccomend getting a par meater insted, lux is light, par is photosyntheticaly available light.
hth,
Whiskey
I think my skimmer is running wet intermentantly, and I think that is causing some issues as well. (my tank is bb) (MR-2 order in the works)
My current light caculates out to at least 220 par in all areas, but some areas are higher than 350 but I can't mount the lights any higher.
I don't think a LUX meater really converts to par quite that easy though, I would definitally reccomend getting a par meater insted, lux is light, par is photosyntheticaly available light.
hth,
Whiskey
I feel your pain on the depth thing. I have a 75, and it is hard to get the lower light lovers satisfied. The best way that I have found to shadow them in the corners. Thanks for all of your help! Unfortunately, I have already ordered a lux meter. 
So I guess, I will be converting to par. Later
So I guess, I will be converting to par. Later
Horace
New member
<a href=showthread.php?s=&postid=6923983#post6923983 target=_blank>Originally posted</a> by Jpharr
I feel your pain on the depth thing. I have a 75, and it is hard to get the lower light lovers satisfied. The best way that I have found to shadow them in the corners. Thanks for all of your help! Unfortunately, I have already ordered a lux meter.
Thats the problem, Lux does not really convert to Par. I think there are some estimates but nothing is going to give you an exact conversion. The reason is you could take a standard industrial MH bulb that has much less PAR than does a bulb designed to emit photosynthetic wave lengths, but it will still have a high Lux. For that reason you should not rely on Lux readings..
Wiskey
New member
This is true, par only measures certin light, where lux measures a much wider specturm, much of it unuseable by plants/corals.
I do use mine to get an idea of how much of a change lowering and raising my MH lights make, how much better/worse diffrent reflectors are, finding higher/lower light areas in my tank (I am amazed how spotty MH lights are) and finding when my bulbs need replacement.
They are quite usefull, but not the end all, be all, of lighting measurement.
Whiskey
Wiskey
New member
<a href=showthread.php?s=&postid=6923983#post6923983 target=_blank>Originally posted</a> by Jpharr
I feel your pain on the depth thing. I have a 75, and it is hard to get the lower light lovers satisfied. The best way that I have found to shadow them in the corners. Thanks for all of your help! Unfortunately, I have already ordered a lux meter.
To convert to par you are supposed to devide the reading by 71 I think, but I am beginning to think that this is not accurate. I think if I had the capeablility to measure par, I would have a much higher reading than I get by this equasion.
ClkWrk posted a picture of his tank with the lux readings on the corals, from what I remember it ranged from something like 22,000 to 6,000 lux, and he has what I would concider a "high" light tank. It is a 120 with 3, 250W MH over it. I was told by somebody else to shoot for around 10,000 lux.
HTH,
Whiskey
Weatherman
New member
Reference for converting LUX to PAR:
http://www.apogee-inst.com/conv_lux.htm
15,000 to 25,000 is a good LUX range to shoot for, for animals that need fairly bright light.
http://www.apogee-inst.com/conv_lux.htm
15,000 to 25,000 is a good LUX range to shoot for, for animals that need fairly bright light.
Wiskey
New member
The thing that makes me wonder about that is it does not take into account what spectrum the MH is.
If you had a 10,000K MH emitting 14,000 LUX and a 2,000K bulb emitting 14,000 LUX the accual par of each would be very diffrent even though the LUX is the same. You could even have a MH emmiting light very close to the IR band that emits the same amount of LUX (14,000) even though almost none of the light is PAR (Very close to 0).
Am I thinking wrong here?
Whiskey
If you had a 10,000K MH emitting 14,000 LUX and a 2,000K bulb emitting 14,000 LUX the accual par of each would be very diffrent even though the LUX is the same. You could even have a MH emmiting light very close to the IR band that emits the same amount of LUX (14,000) even though almost none of the light is PAR (Very close to 0).
Am I thinking wrong here?
Whiskey
Weatherman
New member
That's why LUX meters are not the best choice for measuring light in our tanks. They are highly biased toward the nice yellow-green light our eyes are most sensitive to.
For the price, Apogee Instrument's QMSS-SUN Quantum Meter is the best choice for measuring light in our tanks.
Wiskey
New member
As I do some reasearch here I am seeing this more and more, I have also seen conversions ranging from 50 LUX = 1 PAR to 74 LUX = 1 PAR this is all specific to MH lamps. The one I keep running across is 1 Par = 69.1 LUX but if you had a lamp that puts out all green then this means nothing like you said.
Just adding to the mess of problems,
Whiskey
I have already read the first two, and look forward to reading your next article. Thanks for posting!! I know there are not a lot of people that use them, but have you done any test on odyssea ballast or bulbs sold by aquatraders? I haven't seen in, so I am just curious. Thanks again!
