Non-Oxidizing Biocide

Is microbial growth fouling your system? If left unchecked, microbial contamination can reduce heat transfer efficiency, cause corrosion and create potential health and safety issues.

AQUAGUARD 603 is an effective broad spectrum biocide that can be used to immediately inhibit microbial growth at low dosages.

Unlike other biocides, AQUAGUARD 603 is highly effective at low use levels on a broad range of microorganisms including algae, bacteria, fungi molds and mildew. AQUAGUARD 603 is also highly stable allowing it to be used in a variety of processes over a wide pH range, at elevated temperatures and over extended periods of time.

Biofilms commonly buildup on system surfaces and can reduce heat transfer efficiency, microbially induced corrosion, failure of other water treatment chemicals and potential health effects due to the pathogenic organisms that they may harbor. These films are often difficult to remove with conventional biocides as their polysaccharide matrix protects the microorganisms that make them up from rapid environmental changes including the application of biocides. AQUAGUARD 603 has been proven to be effective at killing the microorganisms that exist in biofilms and prevent biofilm regrowth when regularly dosed in the system.

Formulated with isothiazolone chemistry, AQUAGUARD 603 is non-oxidizing and formaldehyde-free.


  • Effective, broad spectrum antimicrobial agent (biocide)
  • Economical. High stability allows it to be dosed infrequently at low levels successfully
  • Eliminates biofilm and prevents regrowth
  • Non-oxidizing and formaldehyde free
  • Does not contribute to foaming
  • Effective over a wide pH range and at elevated temperatures
  • Low environmental impact due to high performance at low use levels
  • Readily biodegradable when diluted to less than minimum inhibitory concentration (MIC)


AQUAGUARD 603 is registered for use with the Pest Management Regulatory Agency (PMRA) for use in pulp and paper systems, cooling towers, oil field injection waters and metal working fluids.

Click here to view the full product label.

Here’s What a Guardian Chemicals
Partnership Looks Like
Step 1
Get in Touch speech bubble icon
Get in touch

Our experts know your industry and will seek to understand the unique challenges of your business. Let’s talk.

Step 2
Truck icon
We come to you

Your systems and processes are interconnected. We’ll arrange a site visit to understand the bigger picture.

Step 3
Lab test tube icon
We propose a solution
A solution is more than just a product—it is a complete program that results in lower life cycle operating cost and considers the impact on health, safety and the environment.
Step 4
Delivery box icon
We deliver fast
Our service is key to your success. We deliver with industry-leading turnaround times, and effective commissioning and training ensure that your system operates safely and effectively from day one.
Ready to Experience the Difference Guardian Chemicals Can Make?

Talk to our team for advice, quotes, and purchasing.

Contact us headphone icon
Contact an industry expert: