If using a reverse osmosis system to create your own RO water make sure to follow the manufacturers recommendations for changing the filter membranes as over time they become less effective.
A total dissolved solids (TDS) meter is a handy way to understand how well an RO system is working as it (mostly) measures the amount of minerals in the water.
Over time the TDS level will start to climb indicating that it's time to change the membranes.
For complete details see our Water Adjustment article.
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