I recently started using a WFP with my work - which is mostly gutter cleaning with some window cleaning. As I only using around 300 - 400 litres a week, I have started with a dual DI set up (1 before tank, 1 before pole), with some pre-filters (carbon, sediment etc). Whilst not the most cost effective, it is currently the easiest way with my parking situation & access to water/drains etc. Plus the DI's were free! I've been offered a water softener vessel (for free), but I am unsure if its worthwhile. My TDS is 230ish after the pre-filters, taken down to about 30 after the first DI. I know that the ion exchange resin in the softener will increase my TDS, but will the softened water be less harsh on my DI than the hard water that goes through it at present. I tried researching online, but couldn't really come up with anything. Any help gladly received!