anyone have par readings on power compacts?

[nemo g]

ive noticed my monti digis with growths of about 1/4" in about 2 weeks in a 10g under a 65w cusa pc bulb. the frag tips are within 7 - 12 inches of the bulb and have shown great tip extension under this light( the tips - several on each frag - have become larger and longer showing signs of skeletal growth and formation).

ironically, though they were frags from the same mother colony, each came from different set ups. one with halides, the other with a tek, where they barely had any visible "white tips", signs of growth, if any.

everyday few days, the tips look like the skeleton is growing with slight seperation and elongation. for example, what was once a thick looking branch tip is starting to widen and look like a "paw".

back to the question. i am wondering what the par reading under this pc is, and what i should expect when they are under my new maristar that has a giesemann coral bulb with a par rating of 101.

ive read on how certain conditions can bring about growth, and wonder if the higher intensity could ever be "bad" (after acclimation) ?

luckily, these arent plating or encrusting montis that like deeper water. so im hoping the digitatas will take to the new light intensity.

but still would like to have some real world data telling me how much more intense my new250w hqi halide is going to be compared to my 65w pc. especially useful would be with given distances. so i can plot areas of intensity for a given location under each lamp and thus find a similarly lit area for easier acclimation.

so any data sites or books would be greatly appreciated.

nG

[yoshiod9]

i recall seeing a guy using a quantum flux meter when he set up his greenhouse prop system a year or two ago-- i can't remember the exact numbers but i believe a 400w 10k mh had a reading of something like 1000 and the pc bulbs he used had something like 200. feel free to check the coral propagation sub-forum. :D

[yoshiod9]

ha, i found it-- and my memory is failing me, apparently. :) http://reefcentral.com/forums/showthread.php?s=&threadid=246772&perpage=25&pagenumber=10

he tested a 250w 10k and a 55w pc bulb and the par numbers were drastically different than what i estimated.

[reefgeek84]

People will tell you that there is no way that SPS can grow under anything but t-5's, halides...But it is not true. i have monti that is growing under 30 watts of flourencets. You can not keep acro, but alot of monti does fine as long as it is close to the waters surface. People tend to jump on what one person says. if they are growing for you, that is awesome..one more person proving the "bandwagon" wrong. now please for all you people wanting to flame now, I am not saying all SPS can grow under low light, but alot of monti can and does very well.

[nemo g]

thanks yoshi,

great find, and good info. not very scientific, but atleast gives me a roundabout idea, so its a great place to start!

:thumbsup:

[DrBDC]

Are there any threads which check the par/ppfd of t-5's or LED's? There's always a debate on t5's going on but I've never seen an actual review or measurements.

[DrBDC]

Never mind I went searching for "t-5 and par"

[Kip]

tough part about a PAR reading on a floursecent bulb is the energy is spread across the lenght of the bulb wheras a halide is point source and the reading comes from that point. you can take PAR readings at any one point along the length of a flourescent tube, but the findings would be inconclusive.

[nemo g]

kip, yes and no.

the thing is to use the data "correctly".

for example. set a series of points in the tank where you plan on putting corals. then you measure those points. this will allow you to know what corals can be sustained in certain areas and by which type of light.

so, the halide will obviously have more intense light closer to the center of the bulb while the pc or t5 will be ubiquitous and only change in intensity with depth. but that focused center area of a halides output could be far more intense than either of the other two can provide in any single area.

so, if you know what you plan on keeping, you can find out with measurements, where the best places would be for any given coral. in this way, the reading could be useful.

but you are right about a single reading.

a single reading directly under each bulb isnt very tellings. all it tells you is the peak output for each. which is something, but theres so much more needed to know.

[RichConley]

<a href=showthread.php?s=&postid=7521190#post7521190 target=_blank>Originally posted</a> by Kip
tough part about a PAR reading on a floursecent bulb is the energy is spread across the lenght of the bulb wheras a halide is point source and the reading comes from that point. you can take PAR readings at any one point along the length of a flourescent tube, but the findings would be inconclusive.

No, you take par readings where the coral is. It doesnt matter whether or not the light is fluoro, MH, or and open flame. You are simply measuring the amount of photons within a certain range of wavelengths that are hitting that area. The source is irrelavant.

[nemo g]

isnt that what i just sai? :lol:

albeit without the long winded explanation :D

[RichConley]

yeah, pretty much.

[Kip]

well... i read the request for info as "what was the PAR reading of the bulb"... not "how much PAR is my coral getting 18 inches down and off to the back corner"... forgive my interpretation

my answer was based on riding down the interstate in a car with sanjay and my understanding of his reply to my nearly exact same question.

[RichConley]

Its impossible to measure PAR at a bulb. What sanjay does is measuire par directly below the bulb at a constant pre-set location.

Like you said, this is a good way to measure halides, but not a good way to measure tubes.

That being said, theyre all kind of useless, because what really matters is the par reading at a given spot.