How do you get PAR readings?

[perryxcore]

So I keep seeing people post pics with the level of light intensity at different depths of their tanks, obviously there are tools to getting these readings but what is the least expensive and accurate way of getting these readings?

 

[jdreef]

I could be wrong so you'll have to double check but Lux and Parr.. Lux meter is less costly then the Parr meter..Some times you can go to your local reef club and barrow one or your local fish store and rent one.. Either way they both will work.. Hope this helps Good luck..

 

[Paul_N]

The only way to get "PAR" is with one like an apogee Quantum meter (MQ-200) that has a waterproof sensor that can be placed under water. They are around $300 but you could use a lux meter to measure the drop off in intensity of your bulbs. You could measure them when you initially get them and then check for reduction in readings. If the PAR numbers are what you are specifically going after then you need a meter like the Apogee. There is a way to convert lux to par but each bulb manufacturer has a different value that needs to be used to figure it out.

 

[acrotrdco]

LUX meters aren't accurate because it measures the overall brightness, but corals only utilize mostly red/blue spectrum for photosynthesis, therefore PAR (Photosynthetic Active Radiation) meters are more commonly used in our hobby to measure the amount of light that can be used by corals.

You can buy a PAR meter from Apogee Instruments:
Apogee Instruments Quantum Sensor - Measuring PPF