i think there any where between £75-100 all in with del, i use two man once a week i use 750 by myself the rest week and it lasts about 6 months the water i put in between 8-12 ppm week
hope that helps,
I did not put a second comp vessel asi have pushing the new style eco flow to see how it performs- on cut of and compensating between various size hoses, one hose is micro the other is mini-bore
I have just been comparing flow rates water usage speed and ease of use over the last year and longevity of products
i will be perhaps putting system in shed or new van temporary, as i have lot offers on van separately so van is now advertised alone for between £3750-£4250