[easycleaner]

Hi, what tap water tds does it have to be before I can use a DI system only?
Mart

[Ian Rochester]

Anything above 100 and you will be using resin at a rate of knots!

There was a calculation somewhere on here to work out how long resin would last a various

[easycleaner]

Cheers Lionheart that was quick. Any one know the formula for working it out?
Mart

[alanwilson]

formula is

20,000tds per litre of resin - its a rough guide.

for instance, tap tds 100ppm you would get 20,000/100 = 2000ltrs of water per litre of resin.

using 2 di vessels in line means you can use resin that is part depleted to take the tds down from say 100 to 50 before going into the second vessel - resin normally lasts twice to 3 times as long this way.

[Ian Rochester]

Our tap water is near 300 ppm, we use 40" RO's, much, much cheaper in the long run

[JSMC]

my TDS is 28 and will be using twin DI 11ltr tanks

[Nathanael Jones]

www.cleantech.co.uk/tdscalc.htm