[duncan h]

Swapped from 1 single 25ltr DI vessel to 2, just over a year ago.
I cant tell if its using less. Has anyone actually measured the results to compare

[CleanClear]

DI vessel you mean ?

[duncan h]

DI vessel you mean ?

lol yes mate. Altered

[֍Winp®oClean֍]

It all depends on the input TDS of the first vessel. The higher the source water TDS the more efficient the twin vessel system becomes- within a certain spectrum, that is. But to answer your question- yes it does make a difference.

[CleanClear]

yes you will use less resin, you are alternating and only refilling one ?

[duncan h]

yes you will use less resin, you are alternating and only refilling one ?

Yes. I wait till one reads about 003 then use that as the first filter. The second DI with new resin

[Arnold Palmer]

yes you will use less resin, you are alternating and only refilling one ?

Yes. I wait till one reads about 003 then use that as the first filter. The second DI with new resin

To optimise the effectiveness of double DI you should really monitor the output of the first one. Once the resin in the first DI is spent you just burn through the second one quicker.

I don't do that because it's a PITA, I just wait till it's 001 coming out of the second one, you have nothing to gain from waiting. Because of the way it's set up you  only throw away resin that is totally spent.

[JandS]

I have a TDS of around 100 would it be ok to just use a double DI.
Would water production be quicker.
Am on a water meter and hate the sound of waste water going down the drain.
1000 litres gets me 400 pure @ £2.92 per 1000 litres.

[Arnold Palmer]

I have a TDS of around 100 would it be ok to just use a double DI.
Would water production be quicker.
Am on a water meter and hate the sound of waste water going down the drain.
1000 litres gets me 400 pure @ £2.92 per 1000 litres.

It depends how much water you use but probably better with an RO.

[CleanClear]

I have a TDS of around 100 would it be ok to just use a double DI.
Would water production be quicker.
Am on a water meter and hate the sound of waste water going down the drain.
1000 litres gets me 400 pure @ £2.92 per 1000 litres.

I'm lousy at explaining things, but Gardiners resin calculator should help you out......
http://www.gardinerpolesystems.co.uk/Resin_Calculator.htm

I'm also lousy at Maths, but i reckon someone a lot clever than me can work out how it would be with a second vessel. Infact there's a job for Mr. Gardiner........

[֍Winp®oClean֍]

Forget the resin calculator, I have never found them particularly accurate anyway but with twin DI's the older resin is rising in ppm  and so constantly changing.

[jk999]

I bought a 4040 ro 3 years ago with an 11.9 ltr di vessel I asked a question about double di nobody could give me a straight answer so I took the plunge and bought two smaller di s I found my resin was lasting me at least a week to two weeks longer going  through two separate  vessels  .

[֍Winp®oClean֍]

I have a TDS of around 100 would it be ok to just use a double DI.
Would water production be quicker.
Am on a water meter and hate the sound of waste water going down the drain.
1000 litres gets me 400 pure @ £2.92 per 1000 litres.

I would estimate that you would be about equal in cost using twin DI's. Produce water quicker? With twin di's you just fill your van tank with tap water so it's almost instant! You'll also require no holding tank, no membranes to replace, no booster pumps etc etc AND be able to fill up at any source should you run low on water during the day (bear in mind the source water TDS though). Two 11ltr vessels and your van tank is all you require to produce pure water- and it's on-demand.