High TDS is common when retrofitting an existing pool that previously had either a salt or mineral system installed.
If TDS levels are high during the Initial Startup the system will automatically reduce the OXI output (50%) to compensate for the high conductivity ensuring correct output levels. Once the startup process is complete, the OXI output will go back to 100%.
We always recommend diluting the pool water so that TDS levels are ideally below 3000ppm so that you have the freshest possible experience when swimming. TDS will also dilute over time due to rain or evaporation and refilling with fresh water.