Monday, August 07, 2017

TDS (Total Dissolved Solids) Meter

This is a meter for testing water.

We have a reverse osmosis water system under the kitchen sink.  How does it work?  Well, not entirely sure other than by household water pressure pushing the tap water through a semipermeable membrane.  There are several states of filtration and then the water is held in a gallon tank. 

The last time we placed an order for RO replacements, we ordered a TDS meter.

CaptureI think I paid something less than $20 for this meter.  It tests the concentration of solids in the water, particularly salt and high total dissolved solids and nitrates which will conduct electricity within the water sample.  

This thing may be addictive as I will probably be testing water all over the place.  However, the real reason I purchased it is because I was curious about the different types of water  we have available here at home, specifically the water that runs through our water softener.

The process is to place the meter into the samples up to the small ridge, swish it around just a little and then press the “hold” button which holds the reading until it is recorded.  The following are water samples gathered for the test and the results highest to least solids:

Kitchen faucet:  196  water runs through a water softener and a whole house charcoal filter.

Refrigerator:  187  water runs through the above plus a refrigerator filter

Waterline:  170 water sample was taken from an outdoor hydrant that bypasses the house.

Bottled water:  20  Great Value Purified bottled water

RO system in home:  8

We are pleased that our RO system is doing its job of removing the salt in the softened water. 

There is an interesting aspect of RO water that I don’t understand but will mention.  That is that this type of water is “aggressive” to the pipeline on a commercial level.  Minerals have to be put back into the water to keep it from eating through even the plastic pipes. As I understand, the reason is that RO water has a low pH with little alkalinity or hardness to act as a buffer.  (I pretty much copied this last sentence from a web site that was selling RO systems but I believe it is true)  This is why we have our system just inches from where we run it into our glass.

Also, the range of acceptable TDS seems to vary to who is publishing it.  However, there is somewhat of an agreement in a range of 200 to 500 as acceptable.  That would make our water district water very good. 

Bottom line.  We tend to drink our RO water with ice cubes made in the refrigerator ice maker.  However, now that I’ve checked all of the water, I put fewer ice cubes in the glass.