I rented the BRS LED PAR meter and mapped my tank. The readings were significantly different than with our meter. That is not surprising. I think our meter will be very accurate for T5 and metal halide but off a bit with LED systems.
Can you post your results? How much was the difference in the results from our meter? And how long do you have it?
Roughly 100 PAR different at the higher PAR levels and not very much different in low light levels near the sand bed. You can see my results in the picture above. I think I have to ship it back on Tuesday. I'll have to look.