Best Ro/di

[jwils27]

Just wanted to get pointed in the right direction. Also I drink nothing but RO water so this unit would have to have a DI membrane that is easy to attach and take off.
Thanks
Jake

 

[victor626nj]

spectapure make a good one that has 1/1 waste but its coasty...also check

 

[glxtrix]

The filter guys have a nice unit, plus you can take off the separate DI chamber or make your own split so it doesn't go thu the DI nor would you have to detach it. I bought the water general 100gpd one off ebay, it's doing great for my needs.

 

[mapleredta]

yeah thats who i got mine from i didnt want to post that up because they are not a sponsor here.

 

[glxtrix]

They use to be.

 

[roland jacques]

If you plain on using more than 50 gallons a month the Water Saver 1:1 will pay for itself in savings on water and prefilters. especially if your on a sewer system.

And you'll be helping out conserving water. Mine saves me over 20,000 gallons a year

 

[roland jacques]

Water Saver RODI 1:1

You can also just add on the second membrane yourself to an existing RODI.

 

[roland jacques]

Yeap

 

[roland jacques]

Actualy the membranes need to be the same GPD

 

[roland jacques]

It will do both produce more water and less waste. cuts down on prefilters buy about 300%

 

[roland jacques]

No, the waste line from the first membrane (red), is the water in for the second. Then the waste line form the second membrane (red) goes to the resistor.

The clean water lines (Blue) are teed together and go to DI

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[roland jacques]

That one has 3 membranes but its the samething.
It just gets 1.0 gallon water pure 0.5 gallons watse.

 

[roland jacques]

The black lines are bypass valves for testing purposes. When i built this one i had a some nae sayers. So I tested all aspects of this idea to prove it works. Pressure and TDS turned to be just as I predicted.

Mathematical if TDS was the only factor effect membrane life then yes. The life of the second membrane would be 20% shorter than the first, and the third 20% than the second. But in reality the membrane life is not much shorter at all. TDS by itself does not effect membrane life very much. You can find people with 300 tds tap water RO membranes lasting as long as people with 100tds tap water membranes. Some reasons are other things that are more responsible for membrane life than TDS. Chlorine, magnesium, calcium, iron, Solids... I have made over 16,000 gallon of water with mine same membranes with no signs of any degradation. Even if it did shorten the life of the membrane 20% the savings more than off set it.

Our water TDS in GA is VERY low my waste water after the third membrane right now is below 60 TDS. My good water is LESS than 1 TDS before the DI. here an example of how it effect TDS.

TDS
Tap water 100 PPM TDS
1st membrane inlet 100 TDS = 2 TDS good water & 120 TDS waste water
2nd membrane inlet 120 TDS = 2.36 TDS of good water & 144 TDS of waste water
3rd membrane inlet 144 TDS = 2.88 TDS of good water & 172.8 TDS of waste water

So your TDS of your good water is the averaged (because they are mixed together before going to DI) is 2.41333 TDS

Note these numbers are for a 3 membrane unit getting 1:1.
Mine is now different because i reajusted my restrictor to 1 good water to 0.5 waste.

 

[roland jacques]

Bleedingthought;150111 wrote: Understood!

Couple more questions. Is a unit with 3 75g/day membranes in turn making 225g/day? (Assuming it's working in "perfect" conditions)

PSI 60 and temp 65 it would be a little less but . i run mine a 75 psi. and when the water is warm it produces right about that. </em>


And is your TDS level in the 1:0.5 RO/DI water higher than the 1:1?

I just did this current 1:0.5 restrictor adjustment. have not testd the waste water yet. i do expect the TDS to be higher, The good water test 1 TDS.</em>

And how does the math work out since I'm currently at a 1:4 ratio? Wouldn't it be like this per day:

375 gallons go into first membrane.
75 gallons of filtered water is produced while 300 gallons go into second membrane.
75 gallons of filtered water is produced while 225 gallons go into third membrane.
75 gallons of filtered water is produced while 150 gallons go to waste.

And with that said, it would be 225:150. Which ends up being 1:0.67??

Would I have to change my ratio in order to make things work?

My origanal goal was to keep all membranes at 4:1 flush and this is how the math works.

Water volume
1 gallon of water.

1st membrane inlet 1.0 gallons = 0.2 good water & 0.8 waste water
2nd membrane inlet 0.8 Gallons = 0.16 good water & 0.64 waste water
3rd membrane inlet 0.64 Gallons = 0.128 good water & 0.512 waste water.

So you add all the good water you produced it come to .488 gallons and the waste 0.512 gallons (about 1:1)

 

[roland jacques]

in your example
the second membrane wont produce 75 gallons, it would produce 60 gallons

the third would produce 47 gallons

75+60+47= 182
Waste 193

 

[purplegorilla]

How would this affect the input pressure?

 

[roland jacques]

I'm not sure where Russ stands on this. Some vendors are not on board with this Yet. Maybe because they stand to loose sales of sediment & carbon block prefilters, or they dont believe it works... Im not sure. Jim from The filter guys tested this out for himself and found the same results. That why they sell there own version.

Theres a lot of people who lost jobs due to the water restirctions, I think this can be a good way to help out.

 

[roland jacques]

purpleGORILLA;150146 wrote: How would this affect the input pressure?

Pressure
1st membrane inlet 75psi waste 73psi
2nd membrane inlet 73psi waste 71psi
3rd membrane inlet 71 psi waste 69 psi
then resistor. (The pressure Or “back pressure” determines the flush rate of each membrane. This is how each membrane sees a 4:1 flush

 

[purplegorilla]

Well from my understand of what you just said, you dont' really need the ro to be the same GPD as the first one..Just as long as you have one in a series that can handle the pressure. THat is if you are trying to get a 1:1 ratio..However wouldn't it be better to get a higher GPD ro as you gradually add it in the series?

 

[roland jacques]

Bleedingthought;150158 wrote: Roland, are you using a "booster pump"?

No, i tee into house plumbing before the house pessure regulator. I bought a seperate reg for the RO. last i checked Steet pressure around my house is way over 100 PSI.