PAR Meter Broken

[Red_Ant]

So I just borrowed my club's par meter. I wanted to test my new Cozumel reflectors with 250 watt radium bulbs. Well I'm getting par of 60 on the sandbed(24") and 160 PAR 6" from the water surface. The reflector is 8" from the water. From all that I have read online these numbers are coming out way low. The meter is an old apogee with the turn dial that measures PPF. Is there a way to test the meter or calibrate it? I talked to another club member and he was getting almost the exact results I was getting but he had a 14k pheonix. Is there something wrong with this meter? Do I need to do some sort of conversion?

 

[sirreal63]

I would contact apogee to see what is up.

 

[Red_Ant]

Good idea. I will reach out to them on Monday. Anybody else have any suggestions?

 

[Ron Reefman]

Take it out at noon in the full sun and see what it reads. Down here in SW Florida it's about 1400.

 

[Red_Ant]

Gotcha. I will try that when I get back in town.

 

[kc350twin]

PAR Meter Broken

If its the older red or yellow colored box there is a knob to calibrate it on the inside. They were notorious for being off and have to have them calibrated. If you have a multimeter handy you can hook the sensor directly to that and not use the Apogee meter.

 

[Red_Ant]

It is the yellow one. I could get a multimeter. How do I connect the sensor to it? The sensor looks like it connected inside the box. Do I need to open it up to disconnect the sensor?

 

[Red_Ant]

Just ran the "Clear Sky Test" from Apogee's website. The meter is off by 60%. WOW! Calibration is definitely in order.

 

[kc350twin]

Interesting. I'm going to look this clear sky test up.