For those with a par and lux meter can you please tell me what 15k lux is?

[PaleHorse]

That's what I'm getting at the water line with my light about a foot above the water line and the corals 5 inches below that. Thanks

 

[sahin]

Some useful links:

http://www.advancedaquarist.com/2008/2/review

http://www.apogeeinstruments.co.uk/conversion-ppf-to-lux/

From first link: Lux ÷ Constant = µmol·m2·sec
where constant =

<TABLE id=table1 class="listing nosort"> <CAPTION>Lux to PAR Conversion Factors </CAPTION> <THEAD> <TR> <TH>Light Source</TH> <TH>Constant</TH></TR></THEAD> <TBODY> <TR> <TD>Sunlight</TD> <TD>54</TD></TR> <TR> <TD>Warm White Fluorescent</TD> <TD>76</TD></TR> <TR> <TD>Cool White Fluorescent</TD> <TD>74</TD></TR> <TR> <TD>URI (now UV) Actinic Fluorescent</TD> <TD>18</TD></TR> <TR> <TD>URI (now UV) Daylight Fluorescent</TD> <TD>54</TD></TR> <TR> <TD>Actinic/Daylight Combination</TD> <TD>38</TD></TR> <TR> <TD>Philips 03 Actinic Fluorescent</TD> <TD>40</TD></TR> <TR> <TD>Panasonic 6,700°K Power Compact</TD> <TD>72</TD></TR> <TR> <TD>Panasonic 7,100°K / 6,700°K Combination</TD> <TD>55</TD></TR> <TR> <TD>Osram Powerstar Metal Halide</TD> <TD>57</TD></TR> <TR> <TD>Ushio 10,000°K Metal Halide</TD> <TD>54</TD></TR> <TR> <TD>Coralife 10,000°K Metal Halide</TD> <TD>30</TD></TR> <TR> <TD>Venture "Daylight" Metal Halide</TD> <TD>46</TD></TR> <TR> <TD>Radium "Blue" Metal Halide</TD> <TD>51</TD></TR> <TR> <TD>Fusion Sulfur Lamp</TD> <TD>41</TD></TR> <TR> <TD>Westron Mercury Vapor Lamp</TD> <TD>70</TD></TR> <TR> <TD>Iwasaki 6,500°K Metal Halide</TD> <TD>57</TD></TR></TBODY></TABLE>
Doesnt help you directly, but is a start if no one owns both...furthermore it iwll be a VERY rough comparission unless their light course is the same as yours.

 

[Voodoo Corals]

that sounds about right

 

[PaleHorse]

can anyone else please help.

 

[Mark426]

Sahin gave you the best answer you're going to get.

Example:

Lets say you have a Actinic/Daylight Combination T5 setup. Then 15K LUX divided by 38 equals about 395 PAR. (µmol·m2·sec = PAR)

Its a REALLY rough approximation but its in the ballpark.

 

[crs751]

How does this compare to LED's? Does anyone have conversions for this light source?

 

[PaleHorse]

The problem with threads and how they easily get derailed is no one answers the question. They offer help to what they think the question is.

if someone would please help it would be appreciated.

thank you

 

[Eastone]

It's nearly impossible to convert Lux to Par, Par is a measure of active radiation which will vary from bulb to bulb, what sahin gave you is a rough chart to convert par to lux, but again it varies very tightly in regards to bulb, and your lighting combination. I can get 15k lux with LED's and have a wildly different PAR reading should I get that intensity with a 10k metal halide bulb.

What you have is just a measurement of intensity, this will relate to par (more intense light will mean more par) but without a base par measurement of the bulb or your exact setup, it's impossible to know.

Easiest way to test it is to put a monti frag on your sand bed and watch if it colors up or browns, if it browns you're probably in the sub-100 par bracket.

 

[sahin]

15,000 LUX

To convert to PAR = Lux ÷ Constant = µmol·m2·sec

From the table I linked earlier; I took an AVERAGE of all those numbers to work out a ballpark constant figure. So sample constant/number of samples = 52.17 average.

So, 15000/52.17 = 287 µmol·m2·sec

Most likely, no one has both a PAR meter and Lux meter on hand or maybe such a person hasnt seen this thread.

Around PAR of 287 depending on where in the tank you took the reading from is pretty reasonable.