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Total or Free: 
What's the difference? 

AquaSnap™ Total is designed to rapidly assess standards of hygiene, equipment sanitation processes, and the efficacy of Clean In Place (CIP) systems by detecting the presence of organic contamination from microbial and product residues. The honey-comb shaped dipper is coated with an agent that aids in sample collection and extraction of ATP from microbial and other organic cells. AquaSnap Free does not use the agent on the dipper, only detecting free (soluble) ATP in the sample. If using both tests on a sample, the difference in results is the bioload of the sample. The larger the difference the more microbial contamination in the sample. For more information on measuring bioload, visit the Water Quality section.


If, for example:

Total ATP  (cATP + fATP)= 300 RLU


 Free ATP (fATP) = 200 RLU


Bioload = Total (cATP + fATP) - Free (fATP) = 300-200

Bioload = cATP = 100 


Food and beverage facilities most commonly use AquaSnap Total since final rinse water from a CIP system should not have any microbial or product residue.

Total Free Difference

cATPMicrobial ATP  


Total ATP = cATP + fATP