Generally speaking, Bacteria or biocide in general tend to show resistance when the same biocide has been in use for years with no change ( Dosage rate, time of application). THPS and Glutaraldehyde have the same function, so people usually use THPS for a period; then use Glutaraldehyde to instead of THPS ; Rotate it in this way.

Have you got it? If you have further questions on it, please feel free to contact me by 

 whats app: 86-15900587021
 email: amy@shrichgroup.com