Alex
Your sales staff have just informed me that the carbon block was the last pre filter.
And my staff are correct! In typing the above I switched the position of the last two filters.
It should read:
1. Sediment, 2. GAC and 3 Carbon Block.
if you change them every month, is there really a difference aprt from price Alex ?, if I was leaving in like some do for a year , 6 months ect I would pay more, I protect my member and along the flow of water by changing these regular, I do have a very high tds mind :
If you change them every month then you are already spending more than you need to, irrespective of TDS, which is mostly unaffected by the pre-filters. Unless you are using in excess of 1000 litres a day 6 days a week then you are erring on the side of caution.
I would recommend every three months to the average one man band using about 3-400 litres a day 4-5 days a week.