9 Months & Major Drop in Par

[Johnson556]

Recently borrowed an Apogee MQ-200 par meter to see where I'm at 8 months after my initial measurement. I used the same par meter for both tests and the lights were measured at their peak settings.

Lighting is three Kessil A360W's and Six 80 watt T5's housed in a canopy with two fans on the back. One fan is blowing air directly on the ends of the T5's with the ATI logo, and the other is sucking air from the other end. The fans run 24/7 to stop moisture from accumulating in the canopy.

When I first tested the PAR in June 2018 I received the following results, please refer to the image when the tank had a black background. At this time, the Kessils were running at 90% with 45% coloration. The bulbs where almost a month old and front to back went Blue+, Blue+, Coral+, Actinic, Blue+, Blue+. I was averaging 350 on the sand, 380 at mid point, and 420 towards the top of the rocks.

Fast forward 9 months, I borrowed the same par meter to see where I'm at. Dealt with an abundance of problems which led me to drop the power of the Kessils from 90% to 60%, coloration stayed the same. T5's are now 9 months old with no changes. As you can see from the second image the picture is much different. I'm now averaging 240 on the sand, 270 at mid point, and 275 towards the top of the rock work.

At first I just thought, wow a 30% reduction with the kessils resulting in a 30%+ reduction in par, makes sense. Then I increased the kessils back to 90% just to test again and the measurement points only increased slightly, 15-20 par at most.

Did my bulbs really burn out that fast?

 

[jda]

Water clarity could play a factor. Some GAC would probably bring those numbers up. In the first photo, the glass is reflecting light into the tank whereas the coralline in the second is absorbing. Mercury based lights do lose intensity - no doubt... there is some of this in play here. This is probably a bunch of different things.

I would change the T5s after a year, wait a week or two and then measure and use this as your new baseline.

Apogee 200 needs correction factor of 1.32 when using it underwater. I have no idea if you applied this already to your numbers.

 

[Johnson556]

Water clarity could play a factor. Some GAC would probably bring those numbers up. In the first photo, the glass is reflecting light into the tank whereas the coralline in the second is absorbing. Mercury based lights do lose intensity - no doubt... there is some of this in play here. This is probably a bunch of different things.

I would change the T5s after a year, wait a week or two and then measure and use this as your new baseline.

Apogee 200 needs correction factor of 1.32 when using it underwater. I have no idea if you applied this already to your numbers.

I do run GAC, ROX .08 to be exact. Put in a fresh batch 4 days ago. I never considered the coralline effect, good point. I have a new set of bulbs lying around I was going to start changing a bulb out a week until they where all replaced come May.

In regards to the correction factor, I just put down the numbers viewed on the meter. Would this be a 200 reading is actually 264 (200 x 1.32), or 151 (200 / 1.32)?

 

[jda]

200 becomes 264. You multiply.

There also might be a 1.06 on top of this, but I cannot remember off the top of my head. The 210 and 510 meters (ending in 10) have the factors built in already for underwater use and you have to divide if you use them in open air, but the 200 and 500 series do not. Apogee has all of these factors on their website, but it is not as easy to find as it should be... I should have BM'd a link.

Then, you have to factor in that the T5s are going to put out spectrum that the MQ-200 is not going to capture well... like below 420nm, or over 650nm. There is no correction factor for this, so you just have to swag it with your head and eyes.

 

[Johnson556]

Just looked into it, since I used the original meter it required a 1.08 correction, so all figures are actually 8% higher. Thank you for that

 

[jda]

It should be 1.32 and then 1.08, right?

 

[Johnson556]

It should be 1.32 and then 1.08, right?

https://www.apogeeinstruments.com/underwater-par-measurements/

For the original quantum sensor it just says apply the correction factor of 1.08

 

[jda]

It is both. I agree that their wording is bad. 1.08 for use anywhere and 1.32 if you use it underwater for the immersion factor.

The 210 and 510 do not need the 1.08 at all and have the 1.32 applied already to be used underwater, which needs unapplied if you use it in open air.

So you get a 1.425 bump on your numbers.

 

[oreo54]

I do run GAC, ROX .08 to be exact. Put in a fresh batch 4 days ago. I never considered the coralline effect, good point. I have a new set of bulbs lying around I was going to start changing a bulb out a week until they where all replaced come May.

In regards to the correction factor, I just put down the numbers viewed on the meter. Would this be a 200 reading is actually 264 (200 x 1.32), or 151 (200 / 1.32)?

250 goes to 200
Par decrease is proportional to correction factor but its a small-ish error..overall @1.08

Now whether it should be 330 going to 264 is another story..though relative par decrease is 66 (50x 1.32)

Factors are built into either the meter or the software used..or by hand..

the NEW one is 1.32.. The OLD one is 1.08 IF it isn't applied in the METER or the SOFTWARE automatically..

The MQ-210 and MQ-510 Underwater Quantum Meters already apply the immersion effect correction factor to the meter readings through the meter firmware.

 

[blackizzz]

 

[oreo54]

killing glass reflections will kill a lot of PAR from the bounceback..

 

[Cabinetman]

So I have the apogee mq200. So I need to multiply my reading by 1.32 to get an accurate reading?

 

[blackizzz]

So I have the apogee mq200. So I need to multiply my reading by 1.32 to get an accurate reading?

It's my understanding that the MQ-200 has the "original" sensor (the black one), and therefore you should multiply the reading by 1.08

Edit: This applies to all meters with the black sensor except the MQ210 "underwater", which already has the immersion effect corrected in its software.

 

[Cabinetman]

Ok thanks

 

[oreo54]

For clarity.. What 'meter" do you have the sensor hooked to??

 

[Johnson556]

For clarity.. What 'meter" do you have the sensor hooked to??

https://www.apogeeinstruments.com/mq-200-quantum-separate-sensor-with-handheld-meter/

That is the one

 

[oreo54]

Underwater Measurements and Immersion Effect
When a quantum sensor that was calibrated in air is used to make underwater measurements, the sensor reads low. This phenomenon is called the immersion effect and happens because the refractive index of water (1.33) is greater than air (1.00). The higher refractive index of water causes more light to be backscattered (or reflected) out of the sensor in water than in air (Smith,1969; Tyler and Smith,1970). As more light is reflected, less light is transmitted through the diffuser to the detector, which causes the sensor to read low. Without correcting for this effect, underwater measurements are only relative, which makes it difficult to compare light in different environments.
The original quantum sensors covered in this manual have an immersion effect correction factor of 1.08. If you wish to use your meter to make measurements underwater, simply multiply the measured number by the immersion effect (1.08).

also lists some correction/error factors for certain lights..
https://www.apogeeinstruments.com/content/MQ-100-200-300-manual.pdf

 

[alton]

I thought there was a study that showed T5 HO's dropped off fairly quickly but then leveled out, but I can not find it. The ATI with dimming ballast was the perfect idea so you could run your lamps at 70% and then raise them each month to maintain the same PAR levels for over a year.

 

[Cabinetman]

I thought there was a study that showed T5 HO's dropped off fairly quickly but then leveled out, but I can not find it. The ATI with dimming ballast was the perfect idea so you could run your lamps at 70% and then raise them each month to maintain the same PAR levels for over a year.

Bulk reef supplies did the test

 

[Saveafish]

Recently borrowed an Apogee MQ-200 par meter to see where I'm at 8 months after my initial measurement. I used the same par meter for both tests and the lights were measured at their peak settings.

Lighting is three Kessil A360W's and Six 80 watt T5's housed in a canopy with two fans on the back. One fan is blowing air directly on the ends of the T5's with the ATI logo, and the other is sucking air from the other end. The fans run 24/7 to stop moisture from accumulating in the canopy.

When I first tested the PAR in June 2018 I received the following results, please refer to the image when the tank had a black background. At this time, the Kessils were running at 90% with 45% coloration. The bulbs where almost a month old and front to back went Blue+, Blue+, Coral+, Actinic, Blue+, Blue+. I was averaging 350 on the sand, 380 at mid point, and 420 towards the top of the rocks.

Fast forward 9 months, I borrowed the same par meter to see where I'm at. Dealt with an abundance of problems which led me to drop the power of the Kessils from 90% to 60%, coloration stayed the same. T5's are now 9 months old with no changes. As you can see from the second image the picture is much different. I'm now averaging 240 on the sand, 270 at mid point, and 275 towards the top of the rock work.

At first I just thought, wow a 30% reduction with the kessils resulting in a 30%+ reduction in par, makes sense. Then I increased the kessils back to 90% just to test again and the measurement points only increased slightly, 15-20 par at most.

Did my bulbs really burn out that fast?

Shinny new bright and reflecting. Yes you lost par due to loosing the new shinny look. Nothing reflects now like it did when you first took the pic. Rock is not as white, lost reflection, that's means par. Glass don't reflect, that's lost par. Your about right on the par lost.