The TPM value (total polar materials) enables a statement on the ageing of deep-frying oils due to the effects of heat. It determines the total amount of polar materials in % as the reading is showing.
You can filter one fryer after the other:-> VITO VS: up to 3 filtration cycles in a row-> VITO VM: up to 16 filtration cycles in a row-> VITO VL: up to 16 filtration cycles in a rowThe particle filter will last you 6-10 filtration cycles.
Depending on the local regulation in your country, if the number on the tester is still showing below 24% TPM, then you can use the oil as long as the light is showing green and yellow, once it turns into red it's the right time to change the oil.