Tetra’s patented Timestrip allows aquarists to accurately establish when their Whisper filter material is exhausted. Clear water is not a reliable indicator that toxins and other impurities are absent in an aquarium. Tetra’s Timestrip takes the guesswork out of filter maintenance and assists the aquarist in succeeding in his hobby.
Place the Tetra Timestrip in its holder against the Whisper filter or use masking tape to tape it to the back of the aquarium.
Gently press the clear start button or bubble on the Tetra Timestrip. The strip does not need to be oriented in any specific direction.
Wait to see if the white begins to darken. This should happen approximately 30 seconds after the clear start bubble was depressed. If the lower section of the strip does not darken within 30 seconds of having pushed the start button, activate the strip again.
Monitor the Tetra Timestrip. It will change color in approximately one month. Once the strip has turned red, change the activated carbon cartridge in the Whisper filter.
Discard the exhausted strip after you have changed the activated carbon filter material. Activate a new strip as soon as a new filter cartridge is placed into the filter.