At what TDS do you switch the twin DI vessels around?

[slippy]

My DI vessel reached TDS 5, worth waiting until ten before I run it through the second one?

 

[♠Winp®oClean♠]

In reality you've nothing to gain by waiting till it gets to 10ppm. With a twin DI set up you're still going to be using the resin whether it reads 001 / 005 or 010ppm as you're utilizing it to pre-filter new resin. So it will still work for you in the same way regardless./emoticons/wink.png

 

[Damo]

The idea is to have the DI vessels connected in series. So pure comes out of RO into first DI then onto second DI then into tank.

If you producing at say 15PPM from the RO, you wouldn't change the resin in the first DI until it hits 14PPM. Once it hits 15PPM the first DI is doing nothing to help lower TDS. It can actually have a negative effect on the water for the second DI.

You would then take the first DI out. Refill with new resin and then place that in position number TWO. Once the first DI has reached 14/15PPM again. You repeat the process.

 

[Alien Human]

i change it over once it goes anything above 000ppm.

Used to wait till about 7ppm but as has been commented above it just starts acting as a pre filter so don't see the point waiting to change it over.

 

[Damo]

But not swapping it over you are wasting resin.

 

[Alien Human]

Is that for me Damo - I agree with you mate (swap them over)

Worth noting that I'm only twin di (no RO for me!)

 

[Damo]

Gotcha /emoticons/smile.png

Maybe OP is just twin Di

 

[adamangler]

I change mine at 1. I want to know if i get a complaint that its not the water, anything over 2 or 3 i would be panicking

 

[PureWash James]

We have our TDS at 150. We connect two D.I together directly from the tank (we keep everything in the vans, D.I on demand)

When it goes over 5ppm we change the first D.I with new resin and move the second D.I to first.

Saves having holding tanks etc.

 

[slippy]

Yeah I have no RO, just two DIs. TDS is 240. Anyone recommend an RO system? Only need 100 litres a week at the moment.

 

[Fairy]

Tds 240 is quite high