[john39]

my tap readings is 144ppm,used 1000 ltrs through my di yesterday my ppm was 000
and today its 050ppm. anyone any ideas why the big jump?

[Don Kee]

You need an r.o mate.
The higher the tds you put through resin the quicker it runs out....
You're putting quite a high tds through your d.i, were as an r.o would bring it down to 3/4 and then put it through your d.i

[roundbuilder]

Yes defo need a ro unit, from 144ppm you may get it low enough to not need resin also!. Mine is 360ppm before ro then 17 after then after resin 000, i make 2500-3000 litres a week and change resin every 2 months roughly.

[Paul T]

What size DI vessel do you use Mick

[roundbuilder]

What size DI vessel do you use Mick

11 litre i believe. The medium blue 1.

[Paul Coleman]

Using the rule of thumb that I've always used, the resin should give you about 1,500 litres.  However, I'm not sure if that's meant to be 1,500 litres at 000 or 1,500 litres until it returns to tap TDS (meaning that it would be above zero for some time before.

The formula I use is 500,000/tap tds = litres of pure water per bag of resin.  I got my 1,527 litres by multiplying the result by 11 and dividing by 25