Here's redseareef's post...
Hi guys,
Well, first off I decided to measure the tank out with 12 inches dead center in the middle.
After this, useing a marker, I marked off a line from the suface of the water down to the sand. 17 inches total. In 1 inch graduations.
I planned on getting a reading at each mark, so we can see how the PAR drops off at each inch!
Not really knowing what I am doing here, I felt this would give us a real good idea of PAR measurement from top to bottom.
Now, the standard lighting is off from top center. I decided to measure back 7.5 inches from the front of the tank. Which is NOT directly below the light fixture. But these will just be one set of tests. I will do others that are in various spots in the tank. Like I said, the hood is actually set back towards the rear chambers a bit more to allow for room for the front small hinged lid.
This lid I put 2 24w T5's in. So, I will unplug these for the first round of testing to get accurate tests with the standard lighting.
These readings will be based on bulbs with approx. 85 hours on them, and the lens removed. It's removed because I have a cell cast acrylic one being drilled out to replace the original, as it's yellowing and fogging after 6 months of use.
The sensor is very touchy and I got to take a few reading from the 1 inch mark down to the 5 inch mark. Here are the actual readings of PAR on the meter:
At 1" below the surface of the water we get a PAR average of 485
At 2" below the surface we get a PAR average of 450
At 3" below the surface we get a PAR average of 425
At 4" below the surface we get a PAR average of 395
At 5" below the surface we get a PAR average of 330
At 6" below is where my Acropora's are sitting under the lights. I now know for these frags they could stand to be moved up in the water column most certainly. Even with new bulbs and the shielding removed I have seen a notable difference in color and growth! And these are test numbers with the T5's off. I should get about another 100 PAR when these are on.
All my other corals are fine and doing great.
Please keep in mind that there are variables to these numbers. What I mean by this is for instance: My vortech causes ripples at the surface. This indeed causes fluctuations in my readings. Useing a better skimmer will clear water for higher readings. Carbon will give higher readings if introduced to a system that has been ran without it.
I need to make a better holder for the sensor before going any further. I will do this in the morning if I have time. I used a long acrylic rod for these tests, and it's flexing and breaking on me.
For my two Acropora frags at 6 inches, I am guessing they may need up to as high as 6-700 PAR to produce a real glowing effect(flourescense) to be seen.
I will have to post some better pictures of these two frags(A. Gomezi, A Valida(purple Bonsai) so you can get a idea of the colors on these guys.
These lights for all LPS corals and softies are excellent and PAR numbers are fine with great color rendition in my opinion. Some of the easier SPS can be kept under them with no problems at all. Clams I would say no problem either. Mount them up higher!
Crocea's are boring clams anyway, so setting them on rocks is perfect.
I will be posting more data here this weekend. Bear with me and if I make a mistake please point it out. I am new to the PAR meter and testing.
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