# ro/di filter question



## garwood (Oct 27, 2012)

I have a spectrapure 90gpd ro/di system. The water goes in thru sediment then carbon then ro unit. the lines then split and one goes thru di resin then into a bucket to be used. the other comes out of ro unit and down the drain. my question is why is this line not used for other purposes. It looks to me that perfectly good filtered water is goin down the drain. can u not use this water for drinking since it goes thru the same stages as a home filtration system or am I missing something. I know some say to use for washing or garden but what about drinking it?


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## aaron86 (Jan 1, 2012)

The waste water is full of crud that was removed for the filtering process I wouldn't drink it but you could definitely water plants with it


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## twobytwo (Oct 25, 2014)

when you say the lines split, do you mean you have one line coming out of the ro membrane that splits? Or, you have two lines coming out of the RO membrane?

You should have 2 coming out of the RO membrane, one clean and one waste water. You could split the clean line before the DI resin and drink that, but no... you should not drink the waste water.


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## garwood (Oct 27, 2012)

2 lines comin out of ro. I think I get it, the waste water line is the water that does not pass thru the membrane. this excess water creates the pressure that pushes the water that does go thru. but it still passes thru the sediment and carbon tho.


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## Rookie2013 (Jan 17, 2013)

garwood said:


> 2 lines comin out of ro. I think I get it, the waste water line is the water that does not pass thru the membrane. this excess water creates the pressure that pushes the water that does go thru. but it still passes thru the sediment and carbon tho.


I have the exact same system from Spectrapure and hated to see so much of waste water going down the drane. What i ended up doing this weekend is added a second membrane which has reduced the waste water a bit. I used to get a ratio of 2:1 (wastewater to product) with one membrane and now i am at 1.5:1

You can look into this option if you will.


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## garwood (Oct 27, 2012)

Rookie2013 said:


> I have the exact same system from Spectrapure and hated to see so much of waste water going down the drane. What i ended up doing this weekend is added a second membrane which has reduced the waste water a bit. I used to get a ratio of 2:1 (wastewater to product) with one membrane and now i am at 1.5:1
> 
> You can look into this option if you will.


That is a great idea. For the price it will cost to install the second ro unit it would be well worth it. less waste and more good water faster. it seems to take about two hours to fill a salt bucket with my unit, alittle less now since I changed the sediment and carbon. does this sound about right?


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## Rookie2013 (Jan 17, 2013)

garwood said:


> That is a great idea. For the price it will cost to install the second ro unit it would be well worth it. less waste and more good water faster. it seems to take about two hours to fill a salt bucket with my unit, alittle less now since I changed the sediment and carbon. does this sound about right?


Yes tht sounds right to me. I believe you are talking about the 5 gallon bucket. Its too early for me to say anything yet but based on my quick examination the second membrane has definetly helped saving me some waster water and producing product water faster. Just clearifying i did not added a second ro unit instead just added a second membrane to my existing ro unit.

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## garwood (Oct 27, 2012)

Rookie2013 said:


> Yes tht sounds right to me. I believe you are talking about the 5 gallon bucket. Its too early for me to say anything yet but based on my quick examination the second membrane has definetly helped saving me some waster water and producing product water faster. Just clearifying i did not added a second ro unit instead just added a second membrane to my existing ro unit.
> 
> Sent from my iPad using Tapatalk


sorry that's what I meant just a second membrane


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## littletnklvr (Nov 1, 2010)

I don't know why everyone doesn't use the waste water, it's not waste it's RO water it goes through a sediment cartridge then carbon then the RO membrane, viola RO water! I use it for top up water, it's cleaner than the original source water, if you drink the source water why not RO water?


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## kem (Oct 19, 2015)

Waste water is what gets rejected by the membrane, it deosn't even go through it, and takes with it most of the salts and sediments that gets filtered off by the membrane.
Therefore, it becomes of lesser quality than what you get from the tap.


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## canadianeh (Dec 26, 2016)

kem said:


> Waste water is what gets rejected by the membrane, it deosn't even go through it, and takes with it most of the salts and sediments that gets filtered off by the membrane.
> Therefore, it becomes of lesser quality than what you get from the tap.


I am confused of this analogy.

Let's put it this way.

Let's say tap water contains element A+B+C
It goes to the RODI unit and let's say the RODI produces water less element A, B, C
The waste water must have contained either element A, B, C, or combination of the three or less.

So the question is....how come the waste water comes out from RODI is lesser quality from the tap water??? Does the RODI also exert some chemicals that make it lesser than tap water?


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## canadianeh (Dec 26, 2016)

For those of you who uses Spectrapure, where are you buying your replacement filters, membrane, and etc?


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## wchen9 (Jan 23, 2014)

canadianeh said:


> I am confused of this analogy.
> 
> Let's put it this way.
> 
> ...


The waste water is more concentrated, it will contain higher TDS than tap water because you have pulled clean water out while leaving the sediments in. It's the same reason why you top up a salt water tank with fresh water, the salts remain in the tank while only the water evaporates which causes the salinity to rise.

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## littletnklvr (Nov 1, 2010)

Ok consider me enlightened never going to use the waste for top up again, Thanks!


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## canadianeh (Dec 26, 2016)

For those of you who uses Spectrapure, where are you buying your replacement filters, membrane, and etc?


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## Rookie2013 (Jan 17, 2013)

canadianeh said:


> For those of you who uses Spectrapure, where are you buying your replacement filters, membrane, and etc?


I buy mine from Canada Corals

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## garwood (Oct 27, 2012)

canadianeh said:


> For those of you who uses Spectrapure, where are you buying your replacement filters, membrane, and etc?


reefsupplies.ca


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