The Anatomy of an HPS Lamp

Last year, I did a deep dive on High-Pressure Sodium lamps. Coming full circle on my last decade of Lighting research and development that primarily focused on LED applications. It was surprising how little current information there was on the inner workings of these components. And most information was on older technology, like single-ended lamps. It's as though when the DE Lamps hit the market in the US, LED was en vogue, and no one bothered to update information on the most efficient PPFD plasma pump to date. I gathered what I could from old resources and reached out to a few vendors and colleagues to fill in the gaps in terminology and components. You can watch a video on it HERE.

Details of components in a DE HPS 1000W Lamp. PDF Version available HERE

Since then I have illustrated and updated some materials worth highlighting in a more digestible format. The key takeaways are: You get what you pay for

• More spent up front can buy you months if not a year or more of viable output

• There are low, mid and top-tier options

• Price ranges from $25 to $100 per lamp. On average, the best lamps should cost $50 to $70 each at wholesale.
  

  

  HPS Degradation Over Time

  A PAR meter should not be trusted.

• PPFD and Yield DO NOT correlate with HPS

• (8-10% on the meter could mean a 30% drop in yield)

• Re-lamping intervals should be part of your SOP

The most Important components are the Arc-Tube and Ignitor. Arc-Tube dictates the quality and integrity of the spectrum initially and over time. The Ignitor can range from non-existent to triple-wrapped coils in premium lamps, i.e., USHIO, Dutch Lighting Innovations, and Agrolux (Gavita) lamps. You can source HPS lamps direct through us and we can facilitate the recycling of your old lamps through our Relamp and Relax program. What follows is an in-depth look at each component: Arc Tube

The arc tube is where the light is generated. It operates under high pressure and extreme heat, so materials matter.

• Made from polycrystalline alumina (PCA), the same class of material as sapphire glass

• Contains xenon, mercury, and sodium

• Mercury contributes blue light to the spectrum

• More mercury = better for veg phase, but requires responsible recycling

Ignitor

The ignitor handles the high-voltage pulse that gets the arc going.

• Often overlooked but critical for lamp performance

• Premium brands like USHIO use robust triple-wrapped leads

• Cheaper imports cut corners here, leading to startup delays or failure

• If a lamp struggles to ignite or re-strike hot, the ignitor may be the issue

Arc Tube Stabilizers

These are the small metal brackets that keep the arc tube stable inside the outer bulb.

• Premium lamps use stainless steel or nickel

• Lower grades use flimsy build, leading to vibration and failure

• Poor support means vibration, misalignment, and early lamp failure

• Especially important in high-bay or vibration-prone setups

Getter

The getter is a reactive metal that helps maintain vacuum integrity inside the lamp.

• Traps unwanted gases like oxygen and hydrogen

• Prevents spectrum drift, darkening, or sudden failure

• Often underbuilt or missing in low-end lamps

• If your lamps darken or degrade early, this is often the reason

Mercury Amalgam

Mercury and Sodium are combine in the plasma chemistry (Hg Blue, Na Yellow)

• Helps regulate sodium vaporization during startup

• Adds blue light to the spectral output

• More mercury = better for plant growth, but must be handled responsibly

• Mercury exposure is a serious environmental and safety concern

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