Sunday, May 13, 2012

Can Calcite Be Used to Raise the pH of RO Water?

Hello -  If i install calcite media filter to increase the  pH of RO product water for  drinking bottle water application , will there be a change in turbidity ,suspended particle s, appearance ,color or TDS?  Is calcite fit for direct bottling  OR do I need any post filtration?
Mr Patel

Mr Patel  –
We have used calcite for many years after RO systems to neutralize the pH and add some calcium and alkalinity to the purified water.    When the water flows through the calcite for the first time, when it is new, there is a lot of white dust and turbidity. 
So we recommend the filter is flushed for 20 – 30 minutes before it is put into service.  But after the initial flushing.. there is no turbidity and the appearance is not affected.
Generally if the TDS of the water is 10 ppm or less, it add about 70 ppm of TDS to the water, in the form of calcium.   You cannot neutralize the pH of the water, without increase the TDS when using calcite.   If you only wanted to neutralize the pH, we recommend sodium hydroxide, which would only increase the TDS by 10 – 15 ppm perhaps.

See this link for more information on calcite media: