[Ian101]

Cant get my 4040 below 7 tds output.

Normally 4 to 5.

As its getting colder Im wondering if its owt to do with ambient temperture ?

[Window Washers]

Water is denser when cold it should work better water companies adjust the flow

[Perfect Windows]

"with higher temperatures, the salt passage increases, flux (permeate flow) increases, and operating pressure required is lower."

From http://www.get-inc.com/ROTechDisc.htm

So, yes, you should expect this.

Vin