Analysis of PAR: DATA CRUNCH!

Spent a whole day on this, so please take the time to comment. Using the GIRS PAR meter (Apogee Model MQ200) I collected PAR data from my Taotronics TT-AL16 Dimmable LED Aquarium Light. First I will describe my expiriment and present the results, then I will provide a review of my light fixture. It's what you can't see that could kill you (or just disapoint)... Using the Apogee PAR meter, Excel, and a bunch of help from my girlfriend I took down some interesting PAR data about my light. I took advice from MrSaltwater Tank's YouTube Video on Reviewing LED Fixtures to shape what data I would collect and how.


What I was able to do:


#1: Using the PAR meter I calibrated the adjustable knobs to positions of MIN, 25%, 50%, 75%, and 100% (MAX) intensities for WHITE and BLUE respectively. The PAR meter is also useful to check the calibration of your lighting if you have an intensity preset feature on your light fixture. Next, I recorded the PAR my tank recieves under light levels of MIN, 25%, 50%, 75% and 100% (MAX) for each of the following positions directly below the light: AT SURFACE, 6" BELOW SURFACE, 1/2 WAY TO SANDBED, AND AT SANDBED. I took data for BLUE and WHITE independantly, as well as BLUE + WHITE at the same time. The data is displayed in my attached figure #1 PAR DATA BY INTENSITY, which simply shows what PAR my light will output at a specific intensity. It is also a testiment to the accuracy of my light calibration since I surely did not have the PAR sensor in precisely at the same position for every data point I recorded, rather it was aproximate. (As suggested in the YouTube video)


FOR SPECIFIC DATA REGARDING THE SPOTLIGHT EFFECT OF THIS FIXTURE SEE ATTACHED FIGURE 3: The spotlight effect of this fixture is over 95% at the surface, and over 90% at the sandbed.


REVIEW: I've had my TT-AL16 since May of 2014 (~6 months). The TT-AL16 is made in China by Taotronics. Besides having directions that I had to spend way too much time decoding, I have never had a problem with the lights functionality.


Problem #1: The "Dimmable" LED feature using knobs to adjust the lighting way out of wack. The knobs click on at 200 PAR for BLUE and 150 for WHITE. Using the PAR meter I found that there is no credibility to the "white dots" one might use to adjust the intensity of lighting between MIN and MAX. The knobs must be turned to the last 1/4 of their adjustable rotation before reaching 25% capacity. This leaves only 1/4 of the potential rotation to adjust a PAR range for Blue (between 400 and 1000), and for White (between 360 and 1000).


Problem #2: Personal Preference: I'd prefer to keep my BLUE at the MAX (1000 PAR) and my WHITE at a MIN that is below the "MIN" I am able to adjust (below 150 PAR). But if you want greater freedom to adjust low end par values that are still above 150 then this is great for you.


Problem #3: This fixture is an invisible "spotlight". I cannot see the spotlight effect in my aquarium but using the par meter it is absolutely clear that relative to the lights MAXIMUM intensity there is a 95% drop in PAR at the surface, and a 90% drop in PAR at the bottom when measured 12" to the side of the lights CENTER. WOW! OVER 90% LOSS IN PAR JUST 12" AWAY!


SOLUTION: To provide more light to the sides of my tank I could increase the output of my WHITE to compensate for the loss in PAR when I raise my light (keeping BLUE at my prefered MAX). I am developing my spreadsheet to allow me to predict the appropriate height of my light to compensate for the loss in PAR due to the spotlight effect. However, realistically, with 95% loss in PAR on the bottom sides of my aquarium, the spotlight effect is so strong, I'm probably better off positioning my corals more accordingly, or buying a second light!


*** WITHOUT A PAR METER I COULD NOT SEE THE SPOTLIGHT EFFECT, NOT SEE HOW FAR OFF MY LIGHT's CALIBRATION WAS ***


If you wish to take similar data and generate charts like mine, let me know, I'm more than willing to help GIRS members by providing my spreadsheet or answering questions!


Thanks for taking the time to read, and look at my graphs. I really appreciate comments.

 

PAR is Photosynthetically Active Radiation & is important for the growth of Corals, algae, and all photosynthetic life. Understanding PAR might help explain some problems, or might just suit your curiosity. GIRS has an Apogee PAR meter for members to use. The spreadsheet I created will also be available to members, contact me for that.

hart: PAR is important. People should care about it! I know I do! I just took a look at your map, it looks like you also spent a lot of time on it, how did that help you?
F.D. Reefer: Your lenses, who are they made by, and who makes your light? I'm not sure I can replace mine or not, I have to check.

 

hart: Thats a great idea, especially if you don't plan to mover your rock work frequently! I move mine at a pace of about once every two weeks because I obsess over it! lol If I get the PAR meter again, I am going to see what my individual corals are getting.

 

My lenses are 90 degree! I'll look into some different lenses. Also I'm wondering how the new lenses effected the par values previously recorded?

 

If Bud can't get it for you, I can try to re up it when I find it on my computer.

 

Attached! Enjoy! If you want the numbers I have those too. Let me know!

 

I also studied the par variation by light intensity in respect to the TTAL 16's dim able feature (which in my opinion is a joke).

 

I think a lot of people have had good luck with the Hydra 52's and ai sol's. I have never personally had anything besides the ttal16 and I didn't like it. Right now I don't have corals, I've just got a t8 that grows Coraline algae like crazy. Fish only. I can't afford a better light at the moment but will probably get the Ai sol's or a t5 mh led combo fixture when I have the money.