AMA With Eric Eisele, Eli Bakofsky, and Adi Rao From GrowFlux

Apologies for the few in one pos, but I’m off the physio.

Is there a limit to your spectrum?
(In terms of what par #s are available).
Could one recreate the spectrum from a Phillips 315w with the high 630nm spike for example?
How similar to a MetalHalide spectrum is achievable for finishing?
(Not many led companies have even mentioned these thoughts)
What are your thoughts on uv? Far red etc?

When can I buy a low cost par light sensor?:+1:

On one controller system can half the lights come on at once, similar to ramping, but more for heat managemt control.
Or are all the fixtures in one room on one control.
Thank you for the AMA.
Sjoerd visser
@plantopinion on IG.


Hey Eric,

In 2014 when you started GrowFlux, were you targeting the cannabis industry right away if not how long have you been providing your lights to the cannabis industry?

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HI Nick!

Short answer: GrowFlux offers the best return on investment over the lifecycle of the product in part due to our Precision PAR technology which manages the output over time so your yields don’t suffer as the LEDs slowly decline in output. We are the only manufacturer who does this.

On the tunability front, we are documenting some incredible ROI in relation to reducing time to harvest and enhancing product quality with finishing Light Formulas. GrowFlux offers the widest tunability range in the industry and has the only product which is tunable without sacrificing output. We hope to get some of these white papers published later this year. Follow @Growernick for his progress on these fronts.

Finally, something we are increasingly doing with customers is getting involved in cultivation facility design early on since we are able to collapse the installation costs with pre-fabricated electrical distribution. We draw on data center design tactics and suppliers for these services and are able to significantly reduce construction costs.

I could go on and on. And we do on our blog, where we are looking to educate customers, and maybe along the way convince them to buy our products!


Hi Will - we are working on some whitepapers that will first focus on reduced time to harvest via tunable spectrum. We have a rather detailed pipeline of studies under way but that is the first which we hope to put out before the end of the year. Also stay tuned for more on Finishing Light Formulas


Hi Kareen! PPFD, also known as Photosynthetic Photon Flux Density, is a measure of the amount of photons (light) that falls on a given area (in square meters). When we informally say ‘light intensity’ we mean PPFD. PPFD should not be confused with PPF, or Photosynthetic Photon Flux, which is simply a quantity of photons and is not associated with an area unit.

There is actually an ASABE standard that covers all of these measurements. We talk about that standard on our blog: Horticulture lighting standard ANSI/ASABE S640 — GrowFlux


Thank you for your detailed response. I am starting to learn and correlate all this aspects together and see their effects. I must admit I am overwhelmed with the complexity of all aspects involved. could you please provide me with good tutorials/articles that are practical and help me understand the functions and correlations of all these factors better?


Is there a limit to your spectrum?
(In terms of what par #s are available).

Yes there are limits, defined by the spectrum of the individual LED channels and the installed power in the fixture.

Could one recreate the spectrum from a Phillips 315w with the high 630nm spike for example?

We can come close to a similar PAR distribution (for example having a certain amount of PPF in the 600-650 nm range) however unless we specifically put in 630nm LEDs we cannot get that spike.

How similar to a MetalHalide spectrum is achievable for finishing?

I can get you a spectrum comparison after the AMA.

What are your thoughts on uv? Far red etc?

We are developing our new Low Profile fixture (FluxScale LP) with both UVA and Far Red capability. Our FluxScale 600TL fixture currently has far red capability, and will be available with a UVA option in the next few weeks. So many uses for both spectra – we wouldn’t put them in our lights unless there was a compelling enough reason to do so!

When can I buy a low cost par light sensor?

We are getting ready to ship our next beta batch of units in November! Otherwise we expect these to be ready for sale in January.

On one controller system can half the lights come on at once, similar to ramping, but more for heat manage control. Or are all the fixtures in one room on one control.

Our controls allow for an unlimited number of zones, so one room can be one zone or many zones. One zone can contain one or thousands of fixtures. There really are no limits to our controls.


Hi Will- The first cost of our solution may be at slight premium of approximately 10% but over a short period of time our solution provides a benefit of many multiples.

Our increased efficiency on operating costs (Sanitizability, Ease of Control, Increased Energy Saving) offset the first cost of our solution easily within the first 12 months of operation.

With our unique tunability one can reduce time to harvest with our flowering light formulas leveraging this tunable broad spectrum and far red capabilities. This conservatively will increase your yield by approximately 8%.

With our Patent Pending PrecisionPar technology we can ensure consistent results over ten years as we manage the output eliminating the need to replace our solution for up to ten years. We have had discussions with cultivators that complain about the necessity to replace their LED lights with in five years or less. Our solution will add a minimum of 10% additional ROI per year.


Hi Alvaro - Our FluxScale series fixtures have only been available this summer. It took some time to mature our wireless hardware (currently on its sixth generation) and our cloud infrastructure so we are ready to scale.

In the early days of GrowFlux, we followed all of the developments in the cannabis lighting space very closely and decided not to introduce a product until we had something polished enough that would be considered something of a game changer.


Guys, thanks so much for taking the time out of your busy days today to thoroughly answer all our burning questions regarding your totally awesome lights! Look forward to the forthcoming performance test and review

GNET :green_heart: GrowFlux


Hi Brendan- Users can control our fixtures via GrowFlux Cloud, our software platform which allows for tuning the spectrum across an extended range and establishing light schedules.

Regarding communications and security:

The GrowFlux Access Point is designed to work with all common firewall configurations and only uses outbound connections on port 443, so firewalls are not an issue. Data is first encrypted on the physical wireless layer using AES-128 and encrypted as well on the application layer using SSL. So we are actually encrypting all of our data twice - this ensures data is private and secure all the way to the cloud.

The GrowFlux Access Point is designed to work with all common firewall configurations and only uses outbound connections on port 443, so firewalls are not an issue for us. We never use inbound connections for security reasons. Data that travels on 443 is encrypted using the AES128 standard on its way to AWS.

The quick start guide for our Access Point which goes over some of the concerns IT managers might have about our networking hardware.

Data security in the cloud is very much a shared responsibility model. In this case, Amazon assumes responsibility for the physical security of the infrastructure and GrowFlux assumes responsibility of the OS, software, firewalls etc.

You can read more about cloud security here: Shared Responsibility Model - Amazon Web Services (AWS)

Lastly, as an additional layer of security, we are rolling out 2 Factor Authentication in the coming weeks. You can read more about MFA & 2FA here: Multi-factor authentication - Wikipedia


Oh, OK. Thanks for explaining that, Eric!

That is very insightful, because PPFD and PPF can be a little confusing for new growers.

This was a great AMA!! Lots of educational and resourceful information.

Thanks Growflux team!!:thumbsupparrot:

Success Coach


Its been a pleasure! We have a busy trade show agenda coming up - we would love to meet some of you in person!


Hi Eric, thanks for hosting. I just attended the Cannabis Science Conference in Portland, and one of the “deep dive” lectures on light was apparently sponsored by Fluence, who claimed that a 1000w HPS only makes 700ppfd, vs their light as 1200ppfd. Even Ed Rosenthal called them out on their flawed science.

Firstly, Fluence doesn’t make any light that puts out 1200ppfd, gen 1 or 2. Of course, a 1000w HPS can put out significantly more, in fact the reflector has a massive impact on the PAR numbers we’ve tested.

Using a standard Nanolux DE 1000w fixture (commercial reflectors) with the Philips Greenpower + bulbs, we see 12-1300ppfd at 30" to the canopy at 1000w. We tested their deep 4x4 reflectors at the same wattage, and hit 4250 PAR at the same distance. Plants can’t use that much light, with out without carbogation, but even dimmed to 660w we still had 2300 PAR and had to terminate the experiment as the lights couldn’t be raised further.

There does seem to be consensus that the best yields are achieved with 1200ppfd for non-CO2 rooms, and 1500ppfd with supplementation. UV-B still needs to become more prevalent in fixtures in my opinion, even in brief pulses throughout the light cycle.

I’m one of those HPS holdouts, as even my 36KW room is air cooled, so the energy savings is minimal. Once my ROI drops from 4 years to 2 (with no yield loss) I’ll reconsider, I figure in 3 to 5 years time.


The math shouldn’t be all that hard. I recommend anyone making a decision on lighting to double check manufacturer claims with some back of envelope calculations. You are about to spend a ton of money - interrogate you lighting supplier to the degree I’m about to pick this post apart. Lets dive into this a bit:

claimed that a 1000w HPS only makes 700ppfd

As for the 700 μmol claim, was this an average PPFD or peak PPFD? If you look at the PAR maps Nate put together for a variety of 1000W HPS bulbs, the measurements on the Philips Greenpower bulb suggest an average number around 650-700 μmol/m2/s despite a center of fixture reading of 1136 μmol/m2/s. I did a quick calculation on Nate’s PAR map and got something around 650 μmol/m2/s average across the canopy. I have attached this calculation to this post. 180905 Philips Greenpower HPS PAR Map calculation.xlsx (151.0 KB)

vs their light as 1200ppfd

If in theory you have a fixture with a total PPF output of 1700 μmol/s on a 4’x4’ canopy and you have no light losses (i.e. reflective walls all around the canopy) as well as a minimal hotspot under the fixture, you should be able to see approximately 1140 μmol/m2/s at canopy (4x4’ = 1.49m2; 1700 μmol / 1.49m2 = 1140 μmol/m2/s). This translation depends a lot on the optics and uniformity – the more prominent the hotspot(s) the faster this calculation falls apart. I can tell you that this is possible with the Samsung LM301B mid power LED, which might be the part Fluence is using.

Now of course in practice there will be some light leakage out of the sides of your racks, so your average PPFD will be a little bit lower than the total PPF divided by your canopy area. If you are considering a low profile fixture for multi tier cultivation, I recommend you look closely at the PAR maps at 6” / 12” / 18” and pick a fixture with the least amount of hotspot at these distances, otherwise you are missing out on many of the benefits of a large area fixture (less prominent hotspot).

We are preparing to announce a new product for large scale multi tier cultivation along these lines in the coming weeks.

We tested their deep 4x4 reflectors at the same wattage, and hit 4250 PAR at the same distance.

As for that 4250 number, this is a center of fixture measurement at 30”, correct? No matter how well that reflector is designed, the center hotspot will still be there to some extent at some distance. I recommend contacting Nanolux to understand the minimum distance at which the deep reflector is designed to function. It is possible that you are seeing a measurement at a focal point where many rays cross, and that the reflector was designed to be used at a different height to the canopy (ie greater than 30").

For the matter, we designed our FluxScale Reflectors to provide high uniformity at a minimum of 30”. I don’t know what other manufacturers are using for materials, but we import weather resistant and highly reflective sheet metal from Germany (Alanod Miro 9033AG) and make our reflectors in the US in accordance with our software optimized geometry.

I’m glad you mentioned UVB – we are working on some pilots with an innovative UVB technology, however we need to do a lot more work to understand the ROI of the UVB capability in relation to UVA Light Formulas, which are a lit easier to pull off due to the wide availability of high power UVA LEDs. I know @Growernick is interested in this – anyone else feel free to contact me!


I LOVE UVB! I have long sworn by the ability of UVB to improve overall cannabinoin/terpene content and a more flavorful smoke. The stress activated response (SAS) within the plant system results in higher-testing finished product. The same principle has been known since antiquity: the shamans knew the trek to the top of the mountain would yield the best cannabis flowers to attain spiritual visions. The shamans would make the perilous journey to the peaks to pick those flowers specifically. At the top of the mountains, there is less atmospheric obstruction and thus, exposure to more UVB rays than the plants grown in the fertile valleys. (same reason your skin burns faster at the mountain top than it does in the valley). These mountain plants produced clearer visions and were the most highly sought out cannabis, reserved for and revered by the spiritual leaders of the community.

I always try to expose my growing flowers to UVB light. It’s one of the chief reasons I so very mush espouse the values of mixed-spectrum light. Thanks for the UVB plug, @EricEisele!


Great discussion! I did not know how to use PAR map, looking into your calculations and interpretations I totally got it now. Thank you!


Do we have any physiological reason why UVA or UVB is increasing some secondary plant compounds?

I would want to see the absorption analysis of the light.

From early work with UVA and UVB I vaguely remember more tissue damage. Do you think you are seeing an injury response? Sometimes damage in plant cells offer some cool results. Think bonsais, we damage the lignene on one side of the plant to increase the density of the cells on the other.