Can I trust my par meter?

[micl10]

I rented a par meter from an LFS (Apogee MQ-510), and i'm a bit surprised at the results. I'm trying to replicate the BRS settings for 20g tank with 1 AI prime, and i'm expecting this:
(feel free to pause vid at this timestamp)

These are my current settings, and i'm expecting the bottom of my tank to have those readings.

However, this is how my tank readings look like. The orange annotations are the BRS 70% settings, and the reds are just just some 15%ish reduction i did. ( i shoulda saved the exact numbers, but lol)

Notice the bottom left measurement at the sand. 230 par vs 125 par i'm expecting.
Notice the top measure 6 inches below the surface, at 420 par (nice). To me, that make sense vs what BRS seem to be saying i should expect of 203?

Anywho, the BRS video was 2 years ago, maybe something happened to AI Prime 16's LED tech that they're just much better now?
I'm planning on mostly softy/LPS on this tank, and hopefully 1 Colorado Sunburst sitting at the 320 area. But I don't quite know if my lighting is too high, or if i should trust these readings. My goal is not fiddle with my lights and mess up tank stability that way.

Do these measurements make sense for an HD prime using the BRS 70% settings?

Also attached is the BRS 70% settings which I replicated for my AI Prime. The fixture is 8" above the water line.

 

[Pistondog]

STating the obvious, different instruments may give different readings.
Also make sure pumps and wavemakers are off to minimize surface agitation effects.

 

[micl10]

STating the obvious, different instruments may give different readings.
Also make sure pumps and wavemakers are off to minimize surface agitation effects.

I believe BRS were also using the apogee MQ-510. one would hope these products give relatively the same readings? Some of these are 50-100% differences.

My other theory is i'm simply not reading BRS's data correctly. It seems to me like they're saying the 6" line are in the 200 par range. i doubt Prime HD is producing 200 Par at 6" below the top of the tank.
And yes, I did turn off pumps and wave makers.

 

[Hooz]

So, the thing is, they test in an empty glass box with no flow, sand or rocks. The minute you start adding any of those things, everything PAR related is subject to change.

That's why using a PAR meter on your tank is so important. Someone else's settings might get you in the ballpark but, literally, every single tank is different. For some reason, people don't seem to get that.

I'd trust the meter on your tank for your setup.

 

[Hooz]

What are the tank dimensions? That also plays a part as the mounting height is dictated by the area you need to cover (to avoid hotspots).

You said your light is 8" off the water, which is the height they used in the video for a 12" cube tank. 10" high covers 18" width, and I think it was 12-13" high to cover a 24" width.

 

[Mako'sReef]

I have neen running 16hds now for 1.5 years. Currently run 7 on 2 different systems.
I run first 4 channels at 100%
The rest at 50%.
I did run uv,v at 140% for awhile but it will melt the lens above 100% from my experience.

In a small tank you will get alot of light reflection off the glass panels which show higher par.
I run mine at 10" off the surface on all systems.
I get 200 par with 2 16hds at the sand which is 12".
I can take a reading with one on later. I get 250 par in my 45 but its only 12" deep and I run 4 across 36".
This is my 30 remote 24x20x18 and its 12" to the 3+" sandbed.
The Nem is getting 200-220 on tje bottom. Good growth with the Nem and corals.
Note: I tried diffussers on one and it was a par killer so I do not use them.
About 8 months between pics. Also note I started with one for several months.

 

[exnisstech]

So, the thing is, they test in an empty glass box with no flow, sand or rocks. The minute you start adding any of those things, everything PAR related is subject to change.

That's why using a PAR meter on your tank is so important. Someone else's settings might get you in the ballpark but, literally, every single tank is different. For some reason, people don't seem to get that.

I'd trust the meter on your tank for your setup.

^^this^^ Each tank will give different reading. Water clarity, rock, flow, reflection etc will all effect reading. Par readings from someone elses tank should just be used as a starting point when setting up the lights on your tank.