How can I assure I get accurate TDS readings?

”Refer to your TDS device manual for detailed instructions and remember that TDS meters can vary. Shake:
Always make sure to shake excess water off the meter before dipping it into a water sample, even if it’s the same water.

After dipping the meter in the water, always lightly tap it against the side and stir the meter to remove any lingering air bubbles or electrical charges.

When taking the reading, always make sure to hold the meter straight up without it touching the sides or bottom of the glass/beaker/cup. The probes should be suspended as close to the center of the water sample as possible.

The longer the meter is in the water, the more accurate the reading will be.

25 degrees Celsius is the ideal temperature for conductivity readings, even if the meter has ATC.

If switching between very low and very high ppm water, always rinse the probes with distilled water to avoid any build-up.”