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Discussion Starter · #1 · (Edited)
So, today I got a new toy in the mail.. A nice, new, 2015 model hoppy PAR meter (from Hoppy).

In the interest of science and playing with my new toy I took some measurements.

Now disclaimers on accuracy:
1) This is a Hoppy meter, not a professional instrument, that said it seems to be roughly correct.

2) I am not particularly experienced with PAR meters. In general my measurement technique was to move the sensor around a bit looking for a "hot spot" and record that value. This method may result in numbers higher than others report.

3) All distances are from the face of the light to the base of the sensor. The sensor housing itself is about 1" tall, with a sensor buried somewhere inside it.

4) my in-tank measurements were done with the left side of my tank semi-cleared out, but the right side deeply cluttered by ornaments, willow hygros so tall they are spreading over the surface, etc. I found in-tank was highest at about 25% over from the left side. An uncluttered tank would probably find higher numbers closer to the middle.

In air measurements: I stuck the planted plus up on the backs of some high-back chairs, and stacked various household items to get the desired height. Room lights were off, but some dim light spilled in from 2 rooms over (0 on the meter).

30" planted+ in air, blue nightlight off, dimmer bypassed:
12" 59 PAR
13.5" 48 PAR
15.5" 41 PAR
17.5" 32 PAR
18.25" 30 PAR
22.75" 21 PAR

In-tank, 18.5" from light to substrate, 1.25" of air headspace, no lid, blue off:
direct wired (dimmer bypassed): 43 PAR
with dimmer on 100%: 41 PAR
with dimmer on 90%: 33 PAR

In-tank, 18.5" as above plus freshly cleaned glass top, blue off:
with dimmer on 100%: 36 PAR
with dimmer on 90% 28 PAR

In-tank, 18.5" freshly cleaned glass top, blue on:
with dimmer on 100%: 37 PAR


Some general conclusions:

at 18.5" deep, water focuses light quite a lot with a planted+, going from 30 PAR in air to 43 PAR, despite being slightly deeper and having the far 1/3 of the light obstructed by leaves is quite significant. In fact a 43% increase against the odds.

My glass topper, as one might expect, cuts par about 12-15%.

My dimmer on 100% has some noticeable light level losses (about 5%).

The blue LEDs contribute relatively little to planted+ PAR, only adding 1 PAR at 18.5" deep.

The 37 PAR number for in-tank with the topper, blue lights and dimmer at 100% should scale up to 38.8 without the dimmer. This fits with the algae issues I was having with the same setup, and 1.5x excel dosing, and gives me some confirmation the PAR meter is reasonably accurate.

Final note: I'm expecting to be busy for the next week or so.. I'll try to pop in and respond where possible, but if I go a few days without replying don't hold it against me.

Edit 5/29 - I eventually toyed with the meter more and was able to get a reading of 50 for no lid, dimmer bypassed, all leds on.. see post 15...
 

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Discussion Starter · #2 ·
By the way, an image of the in-tank test conditions. The white tube is a chunk of PEX tubing I was using as a wand for the PAR sensor. Willow hygro intrusions visible to right.



Also, this isn't the normal arangement of my tank, I took a buncha stuff that wasn't hard to remove out on the left side (needed some rescape anyway).
 

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These measurements seem very low to me. Someone else measured a 36" with an Apogee PAR meter and had very different results. I'm not caught up with everything that has been going on with Hoppy's PAR experiments though, and I'm not too educated on the subject either, so I have no idea. Just seems much lower than I would expect.
 

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Thanks Jeffkrol, also this video is of the new planted+ 24/7. Although it is not the same fixture it is supposed to compare to the Planted+ in terms of PAR. His meter registered 60 and I'm pretty sure the regular Planted+ has a hair more PAR?
https://www.youtube.com/watch?v=UJsYweqNtig
 

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Discussion Starter · #6 · (Edited)
These measurements seem very low to me. Someone else measured a 36" with an Apogee PAR meter and had very different results. I'm not caught up with everything that has been going on with Hoppy's PAR experiments though, and I'm not too educated on the subject either, so I have no idea. Just seems much lower than I would expect.
That seems surprising to me.. all the Apogee readings I've seen have come back as being on the same order as the Fugeray original. Can you find/link those apogee numbers?

For example in this post:
http://www.plantedtank.net/forums/showpost.php?p=7050730&postcount=12

The 20" planted+ at 18" comes out at 22 PAR, which is less than the Fugeray Original 20", which is 24 PAR at 18".


That said, length is a big factor..

The 30" fugeray is 30 par at 18", while the 36" is 47 par at 18"...

http://www.plantedtank.net/forums/showthread.php?t=189944

That's a 56% increase in PAR despite a 33% increase in LED count (176+16 vs 132+12). That said, LEDs went up by 33% while length only went up 20%.. that suggests higher density in the 36" model so maybe 56% isn't too far off?

If you go by LED count, the 30" planted+ is 104+56+8 = 168 and the 36" is 132+76+12 220, which is a relatively similar 30.9% increase in LED count, again only 20% length increase...

To scale up my in-tank number with no lid of 43 at 18" in water, with no lid.

+30% (by LED count) 55.9 PAR at 18" for the 36
+56% (by fugeray difference) 67.08 PAR at 18" for the 36

That second number puts me in the neighborhood with numbers Jeff cited.. If you read below, that's plausible, and I'd readily accept my in-tank numbers being at least 10% low, no more than 25% low.


I think the numbers I've measured also make rough sense with observed realities... maybe a touch low for the in-water numbers..

At least I propose that based on algae issues:
30" planted+ on my tank with dimmer bypassed and lid on - > 35 par (mild BBA issues n low tech with 1.5x excel dosing)
30" planted+ on my tank with dimmer at 90%, lid on < 35 par (no BBA issues in low tech with 1.5x excel dosing)

And the generally observed behavior that 35 PAR is about the limit when double-dosing excel before you get algae problems.

I measured the second set (with the dimmer at 90%) as being 28 PAR. I could be as much as 25% low (28 *1.25 = 35), but that's really pushing it. I'd readily accept my in-water numbers may be 10% low due to clutter however.

So:
In tank, no lid, measured: 43
10% low clutter factor: 47.3
25% low clutter factor: 53.75

Upscaling those by 30% for the 36" model difference:

In tank, no lid, measured: 43 *1.3 = 55.9
10% low clutter factor: 47.3 = 61.49
25% low clutter factor: 53.75 = 69.875

or 56%:
In tank, no lid, measured: 43 = 67.08
10% low clutter factor: 47.3 = 73.78
25% low clutter factor: 53.75 = 83.85
 

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The video I linked was a 20 gallon high and I assumed he had a 24 in fixture but ne never says. 20 high would be 18 inch high and he probably has 1.5 inch of substrate.

Sent from my VS980 4G using Forum Fiend v1.3.3.
 

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That seems surprising to me.. all the Apogee readings I've seen have come back as being on the same order as the Fugeray original. Can you find/link those apogee numbers?

http://www.aquaticplantcentral.com/forumapc/lighting/89697-par-data-mini-review-finnex-planted.html

I got an early Christmas present: and Apogee PAR sensor
Next up, the new [Ebay Link Removed] Planted+ LED[/URL] in 36". It's a nice light as well, roughly as intense as the AH Supply LEDS, but the spread is not as good. The addition of the red LED's is nice, making colors appear just a touch cooler than a 6700K & a CoralLife plant bulb dual T5. These values were taken in water, so what you see is what you get.

 

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I think hoppy also had said that his meter does not read the portion of the spectrum around 660nm reds perfectly. If I'm not mistaken, the planted plus and the 24/7 get quite a bit of their power from the reds in the fixture.

This meter is a really good value. It is not meant to be a substitute for an apogee. It is, however, a good point of reference and I love my new one!
 

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Discussion Starter · #10 ·
Jeff, fair.. I'd always thought those numbers were from an early hoppy model.. I stand corrected.

Nate: true, although the 2105 model does have some response at 660, unlike the Apogee.. it's not perfect, hence caveat 1.

Also, the 24/7 DOES NOT have ANY 660nm red in it. It has RGB leds, and their red component is in the common 620-630nm range.

620-630 spectra confirmed by Lowe:
http://www.plantedtank.net/forums/showpost.php?p=7569570&postcount=101
 

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Discussion Starter · #11 ·
Oh, one other experiment I did..

I stuck the hoppy meter sensor right against the plastic cover for the lights. I picked a spot where a red and white LED were split by a screw, with only 2 leds in that row.

putting the sensor directly over the red LED got me around 800 par
Putting the sensor over the screw got me around 700.
putting it out past the red got me 500.
putting it over a white LED got me around 1800.

Based on this, you can see the sensor isn't very sensitive to the 660nm red, but does pick it up some (although the background of reflected light from the whites is pretty intense...)

It's a shame I can't put the fixture into 660 only mode.. perhaps sometime I'll take the cover off and mask the white leds so I can measure a 660 directly...
 

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natebuchholz said:
I think hoppy also had said that his meter does not read the portion of the spectrum around 660nm reds perfectly. If I'm not mistaken, the planted plus and the 24/7 get quite a bit of their power from the reds in the fixture.



This meter is a really good value. It is not meant to be a substitute for an apogee. It is, however, a good point of reference and I love my new one!
I could swear he said that in a post. Red and I thought blue but i can't remember the thread

Sent from my VS980 4G using Forum Fiend v1.3.3.
 

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Discussion Starter · #13 · (Edited)
He has the curve for the 2015 version of his meter in his post on the for sale forum. It is also in his diy thread, but you have to dig to get what he settled on.

Ok, now that I have access to a computer:

This is hoppy's for sale ad:
http://www.plantedtank.net/forums/showthread.php?t=841329

One of his older combinations is graphed at the bottom of this post:
http://www.plantedtank.net/forums/showpost.php?p=4358977&postcount=2

The new version seems to have better blue and 660nm red response than the apogee, but does have a bit of a dip around 630-ish...
 

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Discussion Starter · #14 ·
FYI, I just tried the same meter against a 20" stingray on a 10 gallon with about 2" of substrate, 12" light-to-substrate distance, open top..

If I positioned it *just* right I got 40 PAR, but in general I was reading 38. A glass Lid dropped it to 35 PAR.

That seems a tad strong to me at first glance, but is not terribly inconsistent with Aquarium co-op getting 30 PAR out of a 24" stingray on an open-top 20H. A 20H is 16" tall, the light sits almost 2" above the rim, and they had very little substrate, so that's 17-18" down.
 

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Discussion Starter · #15 ·
By the way, I did a quick revisit of this tonight, spending a bit more time finding good measurement spots, etc.

In tank, no lid, dimmer bypassed, blue on, 18.5" from light to substrate:

50 PAR

That's a good bit higher than the 43 I got earlier.. Although to be honest I really had to hunt to find a spot and angle to hold the meter at to get that 50...

One thing I've learned about the 2015 model Hoppy meter is that it is quite angle sensitive, ie: its cosine correction isn't optimal... I believe some of the discussion in the design thread eluded to that, calling it more of a "spot PAR" meter..

Perhaps my earlier low readings are a bit of a reflection of me not understanding this aspect very well.
 
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