Quote Originally Posted by Jonathan View Post
Once the tap water had deposited the ions conained within it (which won't be much) you're not adding more so it won't get any worse. Could just buy de-ionised water... some supermarkets have it in 2.5L bottles.
Jonathan is right 4l is a bit low volume. To cool my 2.2kW spindle I have water in 20 L plastic tube of water with 3 holes in a cap. 2 holes for pipes and 1 for submersible 12V pump. Because it's with cap with tight fit there is no evaporation hence no top-ups and no extra deposits. Never replaced so far since filled up. BTW I have RO filter at home but couldn't bother to us it to fill a cooling system. :whistling: