2 measure PAR values in my tank??

[SkolPaFisken]

Does anyone know how to use a Quantum Meter to measure the PAR values of my tank?

Anthony Calfo suggests the Quantum Meter and I can find one for 250 online but I would much rather use/rent someone elses to get my measurements. I'm in Detroit.

Maybe pick up a used one?

Any advice would be much appreciated.

Thanks