Tasty! You're running Horti Platinum low freeq square wave ballasts to fire those HPS lamps, do I remember that correctly?
GARBAGE
The higher pulse rate of the digital ballast does not represent the light of the sun better than a magnetic ballast. One is just different from the other but neither pulse rate alone fully recreates the sun. In fact I could make the argument that since there are no digital signals in nature, then a magnetic ballast is more natural to us than a digital. We live inside an immensely powerful magnetic field of the earth. Analog sine waves are all around us, the moon orbit, the earth orbit, the spin of the earth, musical tones, bio-rhythms. Many musicians and audiophiles will tell you an analog tube amplifier produces a much more natural sound than does a digital or solid state amplifier. The frame rate of a film produces a smooth movement to the eye and a sample rate of music produces a similarly smooth representation of sound to the ear. Neither come close to actually seeing a play or hearing an orchestra live yet both are forms of discrete or digital representation.
Discrete in this context meaning a single frame of a 30 frame per sec movie or a single bit sample of a 320 bit per second musical note. Likewise a single pulse of light from a Bulb being run by a digital ballast at 20,000 pulses a second can be called a discrete pulse. The Hortilux Digital Platinum series ballast boasts a low frequency or pulse 120Hz square wave. The Hortilux Digital Gold series runs an output frequency of 120,000Hz or 120kHz. The Gold has a higher average light-on time per second which provides a higher average intensity light.
If a digital ballast provides a digital voltage and current to the HPS/MH bulb then that means the bulb is seeing a square wave which will cause erosion of materials inside the bulb and failure of the bulb really fast. If you were to be dragged across a floor and you had a choice of being dragged across steel ball bearings or steel cubes which would you choose? Another way to think of it is the car crash dummy, it is smashed against an object or a wall over an over and soon needs replacing. On the other hand if it puts on the breaks and then accelerates over and over it will last much longer, like we do driving a car. In the realm of electrons, protons, and neutrons a square wave of voltage and current is harsh. A nice AC voltage and current is more like the ocean tides rising and then retreating, another example of a sine wave