Anyone using the double DI method

CMRwindowcleaning · Sep 22, 2015

Saw a thread not long ago about someone using two DI's to fill up there tank. I'm thinking of ditching the ro and going down this route. Probably use about 250-300 litres a day fairly hard water area. Just wondering if anyone is using this method and how much they are producing and how much resin they are going through??

Njones · Sep 22, 2015

I've used that method - - it cut my resin usage by about 30%,.. but it'd still have been well expensive to ditch the RO.

CMRwindowcleaning · Sep 22, 2015

I've used that method - - it cut my resin usage by about 30%,.. but it'd still have been well expensive to ditch the RO.

How much water you producing mate? And what kind of ro you got?

Njones · Sep 22, 2015

I'm not doing windows anymore - but when I was I had a pumped 400gpd system from Vyair and used about 1200 litres in an average week.

I had two 19 litre DI's after the RO and I'd go through a bag of resin every 12 - 14 months on average. If I was using DI only I'd have been using a bag every month or more as my tap water TDS was around 400.

How much water you producing mate? And what kind of ro you got?

firefly123 · Sep 22, 2015

hard water area twin di only no

tench0771 · Sep 22, 2015

Saw a thread not long ago about someone using two DI's to fill up there tank. I'm thinking of ditching the ro and going down this route. Probably use about 250-300 litres a day fairly hard water area. Just wondering if anyone is using this method and how much they are producing and how much resin they are going through??

to factors u need to think about 1 is whats ur tds ? ,2 r u on a water meater?

peter rogers · Sep 22, 2015

this all depends on ppm if its above 300 cheaper with ro4040

mark m · Sep 22, 2015

Was it my old video

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CMRwindowcleaning · Sep 22, 2015

Not on a water meter but morally the amount of waste water that I have been producing has been bugging me lately I'm not entirely sure of my ppm out of the tap it's been so long since I last checked! That's the video I've seen mate @mark m what's your tds? And how much water you producing and resin are you going through mate?

mark m · Sep 22, 2015

this was a few years ago when I did not have the space for a ro unit at the time my tds was 240ppm and I was producing 6000litres fro a approx. cost of £70

windowsurfer · Sep 22, 2015

I use double Di when my 19ltr Di resin is not filtering water to 000 my TDS is 96ppm, I have a 11ltre DI. Just started using more pure, so will see how long resin lasts.

tench0771 · Sep 23, 2015

ide stick to ro if i was u and slow fill a ibc tank im shore u can turn the wast rite down ? if u fill slower

Mx19 · Dec 29, 2019

Hi All, Sorry for resurrecting such an old thread, but i thought it may be better than starting a new one.

I was just after peoples thoughts and opinions on wether or not this would be worthwhile for me. After talking with an ex windie mate yesterday he suggested filling my tank with tap water and using the double-di method after the pump?

Firstly Is this feasible?- I don't have the ability to slowly fill a tank at present and with no access to an outdoor tap for any length of time RO is out of the question at the moment hence using it after the pump.

Next, would it be cost effective?

I currently use spotless water and it'll be an hour round trip to fill up, which I do on average 4-5 times a month and use up to about 1500litres per month (Usually around 12-1300) and it'll cost me on average £55 a month in water plus fuel for 36 miles per trip etc which is approximately £4 I think. So for water per month my cost is £75 not including lost time which would take my cost to £250!!

My tds is super high at 340 ish - How much per month do you recon it would cost in resin?

Any advice will be greatly appreciated!

Part Timer · Dec 29, 2019

The trouble with this method, with such a high TDS, ignoring cost is your resin will be used up very quickly so you will have to play it extra safe, thus incurring even more cost. If you're only using that much water can you not double DI into the tank then you know your water is good for the day.

Google resin calculator and this will calculate your resin costs.

spruce · Dec 29, 2019

maxbruffell said:
Hi All, Sorry for resurrecting such an old thread, but i thought it may be better than starting a new one.

I was just after peoples thoughts and opinions on wether or not this would be worthwhile for me. After talking with an ex windie mate yesterday he suggested filling my tank with tap water and using the double-di method after the pump?

Firstly Is this feasible?- I don't have the ability to slowly fill a tank at present and with no access to an outdoor tap for any length of time RO is out of the question at the moment hence using it after the pump.

Next, would it be cost effective?

I currently use spotless water and it'll be an hour round trip to fill up, which I do on average 4-5 times a month and use up to about 1500litres per month (Usually around 12-1300) and it'll cost me on average £55 a month in water plus fuel for 36 miles per trip etc which is approximately £4 I think. So for water per month my cost is £75 not including lost time which would take my cost to £250!!

My tds is super high at 340 ish - How much per month do you recon it would cost in resin?

Any advice will be greatly appreciated!

As per @Part Timer.

Here is Gardiner's resin calculator to help you make an informed decision.

https://gardinerpolesystems.co.uk/Resin_Calculator.htm

Using double DI will save a little resin but I would ignore this in your calculations.

CMcB · Dec 29, 2019

@maxbruffell I use double di after the pump, I fill my tank with tap water. Though my tds is not as high as yours. I dont have prolonged access to an outside tap either.

The resin calculator is fairly accurate for cost in my experience.

Couple of ideas if you do go down that route: get the biggest di vessels that will fit in your van(25L), that way resin changes will be less. Also, daqua sells a quick change di vessel that is very expensive but seems more efficient, I would ask him about these especially if this is a long term option for you. If they are more efficient etc. And, get an in-line tds meter, if you dont already have one.

Mx19 · Dec 29, 2019

Part Timer said:
The trouble with this method, with such a high TDS, ignoring cost is your resin will be used up very quickly so you will have to play it extra safe, thus incurring even more cost. If you're only using that much water can you not double DI into the tank then you know your water is good for the day.

Google resin calculator and this will calculate your resin costs.

Would i be able to fill at the normal tap speed? Or would reducing speed increase lifetime of di resin?

Part Timer · Dec 29, 2019

With double DI I would think it would be at tap speed but if you're only using a few hundred litres at a time then personally I'd stay topped up rather than going to empty and then filling. I'm led to believe if you don't pack your DI then this will help flow and allow you to shake resin to prolong its life. Others might correct this

Pjj · Dec 29, 2019

Simple answer is no not unless you want to be spending huge amounts on resin your tds is to high for cost effective di only

Mx19 · Dec 29, 2019

Pjj said:
Simple answer is no not unless you want to be spending huge amounts on resin your tds is to high for cost effective di only

Do you reckon it'll cost more than £250 a month for 1500 litres?

Part Timer · Dec 29, 2019

maxbruffell said:
Do you reckon it'll cost more than £250 a month for 1500 litres?

By the resin calculator @spruce gave you the link to, it will cost circa 5p a litre. On that basis you're better off with double DI

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