Input on my PAR Measurements

[Tracey Leeds]

I just took good PAR reading using a Seneye on the right hand side of my mixed reef tank. Mostly SPS and LPS. The tank is a tall 55 gallon with a large, glass center glass brace that blocks a decent amount of light. I was hoping to get some input. I'm thinking I should dial it back a bit. My only concern is my Maxima, which is in the 270 PAR range at the moment. The photograph coincides with the graph. Any help you may offer is greatly appreciated.

 

[Mastiffsrule]

Hi,

You are putting out some crazy par up top. With the tall tank you end up doing that to get the par down low.

My first question alway is going to be, is there a problem that caused you to take readings and maybe change the lights. If everything is good I would leave it. If you are seeing some burning or coral reacting negatively I would back down slowly.

PAR at the bottom can be in the 150 range. The mid 200’s is high. You can lower and adjust you aquascape as needed. Same with the outer edges and the maxima. You may have your lights closer to the water to get that PAR. You can use aquascape along with the par to make sure everyone is happy.

But, tank looks good from what I can see. I it sounds doing good than...

 

[Tracey Leeds]

Santa got me a PAR meter for Christmas. I plan on being in the hobby for the rest of my life. It seemed like a reasonable thing to have on hand. My "wish list" is pretty short at this point, and Santa's little helper made it clear that Santa couldn't afford an Apex. Thank you for your input. I'll dial things down slowly over a couple of weeks and monitor accordingly. Have a Happy New Year.

 

[Dana Riddle]

Are you ramping light? If so, I will calculate a DLI to get a better idea of your lighting. But just off the cuff, your measurements look OK. Give the T. maxima as much light as you can.

 

[Tracey Leeds]

No ramping unfortunately. Just a simple on for 10 hours off for 12. I using 4 black boxes. Nothing fancy. I've been doing this for a while, and I've never heard of DLI. You learn something new every day. Thank you.

 

[Dana Riddle]

No ramping unfortunately. Just a simple on for 10 hours off for 12. I using 4 black boxes. Nothing fancy. I've been doing this for a while, and I've never heard of DLI. You learn something new every day. Thank you.

DLI is 'Daily Light Integral' and reports the total dose of light. Think of instantaneous PAR as number of raindrops falling. What we really want to know is 'inches of rain that fell' which is tantamount to DLI. Lights on 10, off 12 - what of the other 2?

 

[Tracey Leeds]

Nothing other than ambient light in the room. The tank never gets direct sunlight. My lights aren't the fanciest. They don't have a sunrise, sunset option. I can control the intensity. Right now I have blues at 100% and whites on the lowest setting possible. The four fixtures sit 9 to 10 inches above the water's surface and create a literal blanket of LEDs across all but 2 inches of the tank on each end. Thank you for explaining DLI. Taking that into consideration, I may want to cut down on the photoperiod as well as the intensity.

 

[oreo54]

Nothing other than ambient light in the room. The tank never gets direct sunlight. My lights aren't the fanciest. They don't have a sunrise, sunset option. I can control the intensity. Right now I have blues at 100% and whites on the lowest setting possible. The four fixtures sit 9 to 10 inches above the water's surface and create a literal blanket of LEDs across all but 2 inches of the tank on each end. Thank you for explaining DLI. Taking that into consideration, I may want to cut down on the photoperiod as well as the intensity.

As long as you just have on/off w/ no dimming.. DLI calculation:


Here is the formula for calculating DLI with a quantum meter.

1. μmol m-2s-1 x (,3600 x photoperiod) / 1,000,000 = DLI.
2. - μmol m-2s-1 is a reading, or averaged readings, from the quantum meter.
3. - 3,600 is the number of seconds in an hour.
4. - Photoperiod is the period (in hours) of light exposure per 24 hours.

200 PPFD (PAR) for 10 hours = 7.2 DLI

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