Affordable Par Meter?

[vtecintegra]

I wouldn't call it affordable, but I just got a SQ-520. $405, no tax, free priority mail. I found my coral QT and DT were both set about 100 par too high, so it was worth it.

 

[mfinn]

Either SQ-420 or SQ-420x. SQ-420 was replaced with the SQ-420x in the summer (they physically look the same to me). The response curve looks way more accurate on the SQ-420. I was going to buy a 420, but they are out of stock almost everywhere. The next option is the SQ-520, but it's around $200 more. Curve is a lot flatter and supposedly better with LEDs. The 420 worked because it read slightly higher in the higher wave lengths and slightly lower in the deeper blues. So if you measured with somewhat of a full spectrum or white mixed in, it balanced out, and gave a reading close to the more expensive SQ-520. The curve on the 420x looks way out of wack, and probably needs a big correction to get an accurate reading with LEDs. Check out Apogees website.

Ordered the SQ-420, got the SQ-420X.
So exactly what is out of wack.
I've never used anything to measure par. I'm a complete newbie to a par meter.
I've always relied on other users settings for led fixtures. I'm using Philips CoralCare gen 2 fixtures on both my tanks and they aren't real popular in the US right now, so I'm winging it right now.

 

[vtecintegra]

The black dashed line in the photos is the reference line. A perfectly accurate sensor would follow the dashed line exactly.

The SQ-520 is fairly accurate, especially below 450nm (royal blue) compared to the 420.


The SQ-420 (solid black) is less accurate. However, if running a full spectrum light, it reads high above the blues and low below, so the overall number averages out. If running high blue and UV, the number will be low with this sensor.


The new SQ-420x graph looks out of whack. If just measuring 400-450nm it would be ok. Anything full spectrum, it looks like it needs a significant correction applied. At the peak it's reading 30% high.

 

[mfinn]

The black dashed line in the photos is the reference line. A perfectly accurate sensor would follow the dashed line exactly.

The SQ-520 is fairly accurate, especially below 450nm (royal blue) compared to the 420.




The new SQ-420x graph looks out of whack. If just measuring 400-450nm it would be ok. Anything full spectrum, it looks like it needs a significant correction applied. At the peak it's reading 30% high.

So a led fixture that goes to heavy blue, you would get higher than actually is?
And everything else seriously off

 

[vtecintegra]

UV and royal blue would be fairly accurate with 420x. If running whites, no so much.

 

[mfinn]

UV and royal blue would be fairly accurate with 420x. If running whites, no so much.

So it's really not a deal ( at $245 vs. $532 for the 510) if it has such a narrow range.

 

[vtecintegra]

I comes down to personal choice. When I measure par, I'm measuring with blue and white on (some lime also). I want to know what the par is for 90% of my daytime spectrum. I'm only straight blue at ramp up and down. I could have lived with the 420 since it balances out. But Black Friday cleared out the stock at under $200. I studied the graph of the 420x, and just couldn't spend the money and not know how accurate/inaccurate it was. Even Apogee doesn't recommend it for LEDs.

Now, I've got one LFS that runs straight blue and violet. 420x would be ok for that. But that's not my tank. I debated for three weeks what to do and eventually went on the hunt for a 520 at the best price possible. Just got it two days ago. Right off the bat I found I'm 100 par too high on the sand bed. So the entire tank is basically 100 par high. So is my coral QT. 520 I trust, 420 I would be second guessing.

 

[FishyFishFish]

With the new ‘x’ sensors with the poorer response curve, does that mean that we are effectively now restricted to the SQ-520 and MQ-510?

How is the older MQ-210 (non-x model)?

Unfortunately the BRS video was effectively useless in my opinion, due to the fact that some of those tested weren’t working correctly, and they also weren't the models that are currently available.

 

[vtecintegra]

Here is a good example of 210 vs 510. Pretty close. Scroll down to post 53.

LED’s- No UV? Do corals need UV for longterm health?

I lived on the "reef" for three years. You could not snorkel or dive year round in fact you would be luck if you could do it 6 months out of the year. The silt and all of the crap in the water would drop visibility to near zero. This would also impact light penetration. One thing that you can...

www.reef2reef.com

We need someone with the new x version to compare it to the 510/520. Right now, I would rent a 510 over buying a 210x.