Are my T5s to dim?

[Steverd]

I just put an Aquatic Life 48" Hybrid 4-blub fixture over a low boy frag tank.
I only have 40 PAR from my readings, there is no water in the tank yet
and the lights are 15" above the bottom of the Low Boy tank.

The 40 PAR seems really low, is that normal for T5 lights?
Since there is no water, I got out my LUX meter and get 12K-13K LUX

Using 48" ATI Coral Plus and Blue Plus bulbs (2 each)

I am worried I made a mistake with these T5s vs buying 2 or 3 Black box LEDs to put over the tank.

Thoughts please
Thank you

 

[dz6t]

Your PAR meter is wrong, your Lux meter may be correct.

 

[PDR]

Yeah, that's not right. I am running the same bulbs (2 of each) and was getting over 200 par at a 5" depth with the fixture 24" over the tank.

 

[cracker]

lot's of factors involved . 1st the tank has no water & the light is 15 " above the tank. He needs to fill the tank with water then check the par . steve can lower the light, then see. .@Steverd please don't be disappointed with this light 1st off . Lot's of folks use them I like mine far more than leds . I also have black box leds in operation over another tank.

 

[PDR]

I have a hard time believing the par will increase 150+ with some water in the tank... He says he was getting 12000-13000 lux with his lux meter, but the lux on the seneye is only showing 1500. I think something is not right with that seneye.

 

[jda]

Will the seneye work out of water? My Apogee 510 struggles in air.

 

[madweazl]

Measurement is wrong; four T5s will produce significantly more PAR than that; here are some measurements from my 48" fixture (check the "hybrid" tab for T5 measurements only). I believe the results I got are conservative as well but I'm not to concerned with the numbers.

 

[Steverd]

Measurement is wrong; four T5s will produce significantly more PAR than that; here are some measurements from my 48" fixture (check the "hybrid" tab for T5 measurements only). I believe the results I got are conservative as well but I'm not to concerned with the numbers.

NICE chart, what did you use for testing? I may need to buy a different PAR meter.
Here are my LUX measurements at 15" from bulbs. Very steady 12k readings except edges.

 

[saltyfilmfolks]

lot's of factors involved . 1st the tank has no water & the light is 15 " above the tank. He needs to fill the tank with water then check the par . steve can lower the light, then see. .@Steverd please don't be disappointed with this light 1st off . Lot's of folks use them I like mine far more than leds . I also have black box leds in operation over another tank.

You can get a rough “bench test “ with no water. Folks read into that wayyyyyy to much. Most Don’t use Light meters to know that but will still comment.

 

[madweazl]

Measurements were taken with Apogee MQ-500; I wouldnt worry about buying a different meter, I'm not sure why it's spitting out low results but your fixture is putting out significantly more PAR than your meter is showing.

 

[saltyfilmfolks]

NICE chart, what did you use for testing? I may need to buy a different PAR meter.
Here are my LUX measurements at 15" from bulbs. Very steady 12k readings except edges.

On a 4 bulb at about 8 in I was in the 35,000 lux range pretty even across 12 in. Wide tank.

 

[saltyfilmfolks]

Me I'm not sure why it's spitting out low results but your fixture is putting out significantly more PAR than your meter is showing.

How’s that?
Cheap fixtures can do that.

 

[cracker]

Ok Salty , I thought it was an ATI fixture ! This is another big factor involved .

 

[madweazl]

How’s that?
Cheap fixtures can do that.

I'm not understanding what you're getting at?

 

[jda]

Weazl, did you apply the 1.32 correction factor to you numbers? The sensor on the MQ-500 can be in or out of water, but underwater needs all results mutiplied by 1.32.

 

[madweazl]

Weazl, did you apply the 1.32 correction factor to you numbers? The sensor on the MQ-500 can be in or out of water, but underwater needs all results mutiplied by 1.32.

Yes, it was in the notes I believe (guess I better double check).

Edit: yes, the correction factor was there.

 

[saltyfilmfolks]

I'm not understanding what you're getting at?

In more than a few instances , with fluro in several applications , and even in MH in aquarium lightning , it’s been noted that the out put of a light fixture is considerably less than say an ati with the same tubes.
For the op to check , with lux or par , a measurement at a specific distance will tell you if the out put of the fixture differs from the norm.

Personally, I’ve been subjected to a lot of diy fixtures in professional settings that lacked lumen out put. Generally due to substandard parts. Namely the ballast , even though technically the printed specs matched. Quite embarrassing on a Hollywood filmset.

I alway reccomed a measurement at a distance of 12 in in air. That way you know the difference in max output. If a Radion will give me only 40,000 lux and the new maxspect will give me 55,000 , the par is naturally higher. Same for mh using the same bulb.
The only fixture I’ve come across that didnt was made by jbj. The lux par conversion was was close to 80 rather than the norm of close to 60.

 

[madweazl]

In more than a few instances , with fluro in several applications , and even in MH in aquarium lightning , it’s been noted that the out put of a light fixture is considerably less than say an ati with the same tubes.
For the op to check , with lux or par , a measurement at a specific distance will tell you if the out put of the fixture differs from the norm.

Personally, I’ve been subjected to a lot of diy fixtures in professional settings that lacked lumen out put. Generally due to substandard parts. Namely the ballast , even though technically the printed specs matched. Quite embarrassing on a Hollywood filmset.

I alway reccomed a measurement at a distance of 12 in in air. That way you know the difference in max output. If a Radion will give me only 40,000 lux and the new maxspect will give me 55,000 , the par is naturally higher. Same for mh using the same bulb.
The only fixture I’ve come across that didnt was made by jbj. The lux par conversion was was close to 80 rather than the norm of close to 60.

OK, understood. Both of our measurements are on 48" AquaticLife fixtures, the differences between them are the bulb selection (likely the biggest contributor because of the actinics being used) and the mounting height delta (his being 6" higher which would reduce the PAR significantly). I'm using two Blue+, an AquaBlue Special, and Purple+ (the ABS and P+ will likely show considerably higher PAR numbers due to spectrum). Because of this, I believe his meter to be "wrong" and that there is no issue.

Edit: I actually have some Actinics that I could pop in there for an apples to apples comparison.

 

[jda]

With Actinics, they have a lot of the spectrum that a PAR meter will not capture, or only partially captures in the lower part of the visible range, as well as true UV. If you use a better spectrometer, then an Actinic would likely be nearly the same as the B+.

Halides are the same way - lots of spectrum that a PAR meter does not do well with.

 

[cracker]

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