Effectiveness of Biocides

Biocide effectiveness against bacteria, fungi and algae:

Oxidizing Biocides

Chlorine (Cl₂)

• bacteria - excellent
• fungi - good
• algae - good

Usable pH-range 5 to 8.

Chlorine is a powerful oxidant and is used in bleaching and disinfectants, as well as an essential reagent in the chemical industry. As a common disinfectant, chlorine compounds are used in swimming pools to keep them clean and sanitary.

Chlorine Dioxide (ClO₂)

• bacteria - excellent
• fungi - good
• algae - good

Insensitive to pH.

As one of several oxides of chlorine - it is a potent and useful oxidizing agent used in water treatment and in bleaching.

Bromine

• bacteria - excellent
• fungi - good
• algae - poor

Usable pH-range 5 to 10.

Bromine, like chlorine, is used in maintenance of swimming pools. It is also used in water purification compounds, disinfectants and insecticides.

Ozone

• bacteria - excellent
• fungi - good
• algae - good

Usable pH-range 7 to 9.

Ozone is used to disinfect laundry in hospitals, food factories, care homes etc, to disinfect water in place of chlorine, deodorize air and objects, to kill bacteria on food or on contact surfaces, to sanitize swimming pools and spas, to kill insects ...

Non-Oxidizing Biocides

Carbamate 

• bacteria - excellent
• fungi - poor
• algae - poor

Usable pH-range 5 to 9.

Used in insecticides.

Organobromide (DBNPA) 

• bacteria - excellent
• fungi - poor
• algae - poor

Usable pH-range 6 to 8.5.

An effective fumigant.

Methylene bis(thiocyanate) (MBT)

• bacteria - excellent
• fungi - poor
• algae - poor

Decomposes above pH 8.

Methylene bis(thiocyanate) is used as a microbiocide/microbiostat, fungicide/fungistat, algicide, and disinfectant.

Isothiazoline 

• bacteria - excellent
• fungi - good
• algae - good

Insensitive to pH.

Triazine 

• bacteria - no control
• fungi - no control
• algae - excellent

Usable pH-range 6 to 9.

Triazine compounds are often used as the basis for various herbicides.