Total Dissolved Solids - Calculator

STEP 1. Rinse the TDS Pocket Monitor with reverse osmosis water.

STEP 2. Test the tap water first with the TDS Pocket Monitor and write down the results.

 STEP 3. Again, rinse the TDS Pocket Monitor with RO water. Then test your reverse osmosis water. Write down this number.

Tap Water:
RO Water:
  Membrane Effectiveness:


Now that we have the membrane's rejection rate, what does this mean?

The rejection rate is the percentage of the amount of TDS (Total Dissolved Solids) eliminated from the tap water by the membrane. Example: A 90% rejection rate means that 90% of the TDS has been eliminated from the tap water.

If your Membrane Effectiveness is between 100% -75% your membrane is operating within factory specifications.
If your Membrane Effectiveness is 74% or less then we recommend replacing your membrane and the flow restrictor as well as new pre and post filters.

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