Active oxygen is too unstable to guarantee a permanent disinfection of the water. Hydrogen peroxide and potassium persulfate are the best known forms of active oxygen sources. The oxygen level should be replenished when the oxygen level is 35 mg / l.
Shock disinfection is performed at least once a month with concentrated oxygen or chlorine. Active oxygen tends to lower the pH value, which must remain at 7.2-7.6. The active oxygen content can be measured with DPD 4 tablets.