PAR meter calibration

[lilrobb]

Checked PAR on my tank again, didn't change anything and PAR dropped from 600ish to 180ish within the last 6 months.
(T5 lighting)
Does a par meter need calibration, it just doesn't seem right!

Robb

 

[ichthyoid]

I thought that was the MH that had dropped?

 

[lilrobb]

Correct - it was the MH.
The comparison T5 reading showed about a 50% drop over the same period of time...

 

[ichthyoid]

Ah...yes, I remember that now also. Approx. 1/4 on the MH and 1/2 on the T-5's. Hmmm. I guess you could check it against another of the same model if available. I wonder what they charge for recalibration?

 

[raisedonnintendo]

I wonder if the 6 month old bulb need b changed out.

 

[markl]

Id rent the one Tim has and try again.