Running 1000w Hortilux HPS in a 4 x 4 in 25x 3 gallon pots. No Tent. 20 x 20 open room, with excellent fresh air exchange 24/7. Which, IMO, is KEY, to using high light levels.
Buddy got 43.7oz. 1197 Grams- 3 week clone veg, 24/7, under 1000w Hortilux Blue. Every 3 days turn lights off 4 hours.
Strain is 1992 Sensi Seeds NL5 x NL2=aka then as NL5. Buddy has had the mother for almost 30 years. I gave him the original mother, in 1995. NL5, is some of the best stuff there is, when you find a good one. And it was easy, to find a good one. Back then, there were keepers, in every pack of NL5.
1.197 Grams per Watt.
While the HPS produces more vs 1000w HALIDE, I believe the 1000w Blue, brings out more expressions, and more varied chemical/terpene profiles vs HPS, or LED.
Out of a 1150w Gavita DE HPS, 880w Mammoth, 1000w Hortilux Blue, 1000w CMH, the Hortilux Blue is my bulb choice, for bringing out the most expressions, and varied chemical profiles.
MMS, also has a new 1000w/600w/400w Halide, that is a copy, of the Hortilux Blue, but, is 20% more powerful vs the Blue, and is $100usd cheaper. I bought 6 f the 1000w bulbs.
Blue/MMS have a K rating of around 6000k. I believe the sun, at noon, is 5800k. Some of my buddies out in Cali, also feel weed flowered/harvested, in the Spring, is superior, to that harvested, in the Fall. More Blue, in the Spring, and way more intense vs the fall.
Also the Halide has a Spectrum of 280nm-2000nm+. Few lights can match that. I also supply UVA/B in the form of 2x 32w Solacure Flower Power bulbs, in each 4 x 4 and 1000w HID. I also use them on seedlings, and run them from seedling- finish.
Solacure, is the most powerful UVA/B bulb made, that has the majority of its power from 280nm-300nm. It takes special glass, to let this wave length through. It is also a T12, which gives it a HUGE light source, and has a Built In Reflector, inside the bulb.. You Cannot Reflect UVA/B, and this special coating, is the most effective way there is, to waste as little of the UVA/B, vs using a normal reflector. This is T12, and also fits most standard 4ft ballasts, and can be run as high as 80w,, as it is way overbuilt. But, its not necessary, in a closed up environment, like a room. Greenhouse-Yes. We use Solacure Ballasts.
LED Flicker and Health Risks
Like early fluorescent lighting systems, LED systems are prone to producing rapid flickering or stroboscopic effects, and this is a significant area of concern when it comes to LED lighting and health.
Figure 4: Vertical banding in a simple smartphone photo shows that the LED source is not a constant stream of light - instead, they are emitted in short bursts.
Many LED bulbs produce flicker - a rapid switching between on and off states. Because the flickering happens at a very fast rate - typically 120 times per second or faster - it is not immediately observable to humans and appears to us as a light bulb of steady and constant brightness.
Flicker is a difficult aspect of lighting to observe and measure, as it is not immediately perceptible or noticeable, but preliminary research suggests that it can have detrimental effects on health and safety.
In other words, just because flickering is not immediately evident or perceivable to our eyes, our bodies can subconsciously react and respond to what is essentially a very rapid strobe light. Flicker has been associated with eye strain, fatigue, headaches, and even elevated risks of seizures.
Even without the backing of significant medical or scientific research to back it up, it is hard to argue for any positive health benefits of flicker - it is simply not a natural way for humans to be exposed to light. Natural daylight, candles, and even (most) incandescent bulbs provide a steady stream of light without any flicker. Especially for populations that are sensitive to flicker - such as the elderly and those with certain medical conditions - flicker is an issue that is always best avoided.
How to Determine or Measure Flicker
For some LED bulbs with more serious flicker, objects in motion can appear to have a stroboscopic effect. Waving one's hand under an LED, for example, might create the illusion of discontinuous movement.
A common phenomenon you may have observed is dark bands that appear on your phone camera. While some modern smartphones have begun to incorporate software to attempt to mitigate this effect, this is another certain indication that an LED bulb is flickering.
Although the most surefire way to measure flicker is to use specialized measurement equipment such as a oscilloscope, a quick and effective way exists on most smartphone cameras.
Simply use your smartphone's camera app to record a short video clip in slow motion. Most smartphones such as iPhones will be able to record video at up to 240 fps - a frame rate quick enough to capture flickering that occurs in the 120 -360 Hz range, which is also the most problematic frequencies when it comes to the health effects of flicker.
Causes of LED Light Flicker and How to Avoid It
Generally speaking, there are two types of flicker in LED lights. Below, we'll discuss them and what to look for when trying to avoid them.
Flicker Caused by Alternating Current and Insufficient Filtering
The first type of flicker is caused by the AC (Alternating Current) waveform used in power transmission. The electricity that flows through the wires in our homes and offices are actually fluctuating in a sinusoidal waveform with changing polarity 50-60 times per second (hence the term Alternating Current). In an AC system, the electrical current actually switches between on and off states, as well as its current flow direction (from + to -) at 50-60 times per second.
LEDs are DC devices and cannot have their polarity reversed, and therefore are incompatible with AC systems without the appropriate LED drivers and power supplies. The design of the LED drivers and power supplies dictates the extent to which an LED will flicker.
The most basic LED driver will simply rectify the AC signal without smoothing, and simply provide to the LED the inverse of the AC signal when the polarity switches. Because the AC signal goes to 0% 2x times per cycle when the polarity switches, the result is a light emission that switches between its maximum (100%) and minimum (0%) 100-120 times per second (@ 50-60 Hz AC), creating a relatively significant flicker effect.
With more advanced LED drivers, in addition to rectifying the AC signal, additional capacitors are used to smooth out the spectrum during the polarity switch in an AC signal.
Most LED bulb manufacturers, unfortunately, do not publish flicker specifications. When available, look for LED bulbs with a flicker free designation, along with a flicker percentage below 5%, flicker index less than 0.02.
Flicker Caused by Dimmers
The second common cause of flicker in an LED system is in its dimming systems. LEDs are digital devices, and as a result, controlling the output is most practical using PWM (pulse-width modulation). PWM produces a square wave of either "on" or "off" states at a relatively fast frequency.
LED dimmers use PWM to create the perception of dimming by adjusting the relative time durations between "on" and "off" states, but they do so at a variety of frequencies. Basic PWM LED dimmers operate at 300 Hz or lower, while
truly flicker-free LED dimmers operate at 25,000 Hz or above. By raising the frequency to such high rates (e.g 25,000 times per second), the rate of switching becomes so rapid that it is far above the threshold of even subconscious perception for the human body.
Dimmable LED bulbs must combine interpreting an AC waveform's dimming signal and output a corresponding PWM signal, and this most frequently results in flicker rates that are too high.
When possible, avoid the use of dimmers altogether, as they introduce an additional risk factor when it comes to flicker. If dynamic brightness control is essential, avoid "dimmable" LED bulbs, and opt for
PWM dimmers with high frequencies < 25 kHz, and ensure that they are used with
flicker-free power supplies.
Bottom Line
LEDs are a new and exciting lighting technology, but they are not without health and safety risks. By being aware of the spectral content as well as the flicker metrics, you can be sure to minimize the risks of LED lighting on your health and well being.
