What TDS Should Remineralized RO Water Be?

This article is about the numbers: what to aim for, why those ranges exist, and what to do when the reading is outside them.
ro remineralizer  Behind the Taste
For remineralized RO water, TDS is a proxy for mineral content since the starting point is near-zero dissolved solids.
For RO remineralization purposes, that total is dominated by whatever minerals the remineralization method adds, which makes it a reliable indicator of whether the process is working.
Raw RO output typically measures between 5 and 20 ppm.
Why 50 to 150 ppm
The 50 to 150 ppm range for remineralized ro water tds level is not arbitrary.
A TDS reading of 50 ppm from a correctly formulated remineralization method typically covers both minimums.
For aquarium use, the target depends entirely on the species being kept and their specific water chemistry requirements.
When the Number Is Outside the Target
For drops, increase the dose by 25 percent and retest.
For a cartridge, check that you have not accidentally installed two remineralization stages.
how to add minerals to distilled water naturally  between 150 and 200 ppm is not ideal but is not cause for concern.
Avoiding Common Testing Errors
Dip the TDS meter into the sample rather than running it under the stream for a more stable reading.
Replace the meter battery when readings start fluctuating unexpectedly, since low battery is the most common cause of unstable TDS readings.
Know the target before you test, verify after remineralizing, and adjust until the reading lands where it should.