As AI workloads drive unprecedented rack densities, direct-to-chip liquid cooling is becoming essential to high-performance data center operations. But introducing liquid into the IT environment creates a critical operational dependency that is often underestimated: coolant chemistry.
When coolant chemistry falls outside specified operating parameters, the consequences can extend beyond reduced cooling performance to equipment damage, unplanned downtime and significant financial exposure.
To keep GPUs within acceptable operating temperatures, heat rejection must start at the chip with DTC liquid cooling. Unlike the chilled air and evaporative cooling systems used in traditional data centers, DTC liquid cooling systems circulate PG25, glycol based coolant through tech loops comprised of a complex system of pipes, pumps, filters, UQD (universal quick disconnects), rack manifolds, cold plates and heat exchangers.
A lot is riding on the PG-25 glycol coolant running through that system. The success of your cooling strategy is riding on that. So is your ability to avoid costly downtime. And your ability to drive revenue from AI workloads. All of your investments in AI depend on it.
That brings me to a word that hasn’t been part of the data center industry’s vocabulary before: chemistry.
Chemistry matters for DTC liquid cooling.
In fact, chemistry is absolutely critical. The success of those DTC systems requires PG25 coolant to stay within very strict parameters. If the chemistry shifts, bad things start to happen. Things can go wrong very quickly. Here are just three examples:
- Even Small Shifts in pH Can Cause Big Problems – Maintaining the proper pH of glycol coolant is critically important. If the pH gets too high, the result can be significantly reduced heat transfer, corrosion and scaling.. If the pH gets too low, the coolant can rapidly strip the protective oxide layer from stainless steel pipes, dissolve copper from cold plates and cause other elements of the system to deteriorate. Simply put: when pH is not strictly controlled, your DTC system begins destroying itself from the inside and puts your AI operations at risk. The consequences can include overheating, equipment damage, leaks, prolonged downtime and even the need to replace the entire cooling system.
- Contamination and Biological Growth Can Bring Your Operations to a Halt – Coolant chemistry and biological contamination are closely connected. Without effective chemistry management, cooling loops can become vulnerable to microbial growth, particulate contamination and biofilm formation, potentially restricting coolant flow and compromising heat transfer performance. Parameters including glycol concentration, differential pressure, conductivity, pH and turbidity should be monitored against defined operating limits to identify emerging risks and support timely intervention.
- Degraded coolant chemistry can compromise cold plate performance– In many ways, the world “cold plate” is a misnomer in DTC liquid cooling. It is not a flat panel that coolant is circulated over. Cold plates actually have a complex architecture that circulates coolant through ultra-thin fins that are 100 or 50 microns wide. Effective cooling depends on the coolant’s ability to flow freely through these narrow channels. That happens successfully when coolant chemistry stays within narrow parameters. But when chemistry is off, those micro-channels can rapidly become narrower, obstructed or blocked. The result can be rising temperatures, volatile pressure, leaks and damage to the cooling loop and GPUs. When you consider that a typical 2500-gallon cooling may support 64 Grace Blackwell systems, the damage could be in the tens of millions of dollars.
To avoid these scenarios, organizations need to do more than periodic chemistry checks. They need a comprehensive coolant chemistry strategy that begins at the design phase, includes key steps at the commissioning phase and then follows rigorous processes for monitoring, chemistry management and risk mitigation. Key elements of the strategy include:
- Proper Design for Wetted Materials and Cleanliness – An effective chemistry management strategy starts early – well before a data center becomes operations. During the design and commissioning phases, organizations should ensure that all piping, pump components, and cold-plate metallurgy use approved wetted materials to prevent chemical leaching. Proper passivation, cleaning, flushing, and filling must be established before commissioning to make sure there are no particulates from day one.
- Dedicated Flush-and-Fill Infrastructure – One of the most common causes of chemistry issues is improper filling procedures. When data centers lack a properly designed, dedicated flush-and-fill room, human error can cause contamination or mistakes that cause a cascading series of dominos. With proper infrastructure and processes, data center teams can perform flushes and fills in ways that prevent contamination, maintain positive pressure and control glycol temperatures in ways that protect the system and performance.
- Continuous Real-Time Monitoring – Periodic checks are not enough to mitigate chemistry risks. It is important to use automated sensors to track glycol percentage, pH, conductivity, and turbidity in real time. Continuous tracking catches microbial growth triggers and localized corrosion trends early, allowing engineering teams to adjust chemistry before an emergency shutdown occurs.
- Real-Time Data and Expert Lab Analysis – Organizations should pair continuous automated telemetry with deep laboratory testing by specialized chemists. This combination delivers an advanced early-warning system and root-cause clarity to assign accountability, protect SLAs, and refine operational procedures over time.
- Extend Oversight to Facility Water Loops – Chemistry management is not limited to the PG-25 loops. Organizations should also apply continuous monitoring to the primary water loops connected to chillers and cooling towers, mitigating biological and chemical risks before water is cycled or discharged.
These are just a few of the best practices that provide a foundation for effective chemistry management. You can read more in a white paper that I recently wrote with Vishal Kochar at Ecolab, titled “The Importance of World-Class Chemistry Management for Direct-to-Chip (DTC) Liquid Cooling Environments in AI Factories.” To read the white paper, click here: Salute_Ecolab_Whitepaper_US_WEB.pdf.
Salute has partnered with Ecolab to simplify the complexity of chemistry management – enabling data center companies to mitigate the risks of improper chemistry management. Ecolab’s Cooling-as-a-Service provides comprehensive chemistry management for AI data centers that utilize DTC liquid cooling. That chemistry management service complements Salute’s first-of-its-kind DTC Liquid Cooling Operations Service, which enables companies to achieve world-class AI operations that mitigate the elevated risks of bringing liquid into the data center.
In AI data centers, having the right chemistry management strategy matters. And having the right operational model matters. Together, Salute and Ecolab give you both.