Showed up with no battery even though the directions for battery replacement says "To power the meter, slide the included battery (CR2320) into the battery holder, after removing the battery door from the meter’s back panel". So glad I paid for Next Day Air shipping this meter to myself, so I can wait 3 more days to get a specialty battery shipped that isn't sold at any local stores near me. Maybe I'll be back with a better review once I can actually use this device.

I am so glad I purchased - it saved my corals I was shocked with the results and was able to tune my lighting appropriately - it shows in the corals ! (I was under lighting )

Buy the meter! It’s almost as useful as tasting the water to figure out salinity without using a par meter to set up the lights. Buy it!

I've found this unit to be great. It's simple to use and doesnt require connection to a laptop or other device which I find much easier. The only downside is it doent come with the wand, so if you purcahse one, make sure you either buy a wand or make one.

It works very well. Just for fun I set my tank day one using my eye and best guess...I had about 390 par by accident. Thanks to the par meter I was able to correct this in just about 10min time.

While this meter may be towards the "top of the line" as far as par meters go, it simply offers zero water resistant protection for a $550 that's specifically designed to be around water. There's no rubber gasket between the two plastic housing pieces so the moment the screen controller hits the water it shorts the board out. Apogee then wants $75 to replace the board on top of another $30 to ship it back. I'd gladly take a less accurate meter that is more suited for the environment it's going to be in vs having paid this much for a meter that lacks some of the most basic features it should have.

BLUF: Buy or rent one. The MQ-510 PAR meter is a very useful tool that functions exactly as expected and takes the guess work out of placing coral or anything else that is light-dependent. Turns out, the only thing sub-PAR was my original lighting system; luckily the reason for testing was for a baseline for a light upgrade. I would highly suggest using a PAR meter instead of guessing your light output and coral placement. If your reservation is the cost of the meter itself; think of how much money you can lose by misplacing corals or even buying ones that your lights can not support. Only thing I would do different is, buy it sooner.

Great unit, easy to use. Recommend you order with the wand. Was able to move corals to the right spots in the tank for optimum growth.

For the price you’d expect that the mounting stick would be included, or at the very least doesn’t cost an arm and leg for it ($60) a bit ridiculous if you ask me... Unit works fine tho. Now I can feel more confident about coral placement. It’s a good buy if you’re setting up many tanks, or trying a coral in which your not sure what the lighting requirement should be. Or if you change your light. I did the rental at first, but I’m a serial tank tinkerer (can’t keep my hands off the tank!!!

This product is great. Does everything it says it does, Gives you INSTANT PAR and you know your getting an accurate reading. The handheld is also great and super easy to use. Fits in your hand like a glove while you put the meter in the water. I would HIGHLY recommend the wand. Search BRS for: SENSOR WAND FOR PAR SENSORS https://www.bulkreefsupply.com/sensor-wand-for-par-sensors-apogee.html