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Are RO Units Worth The Money And Effort?

  • #21
For the various horticulture applications, I consume between 10 and 20 gallons of RO water each day. (Half of that is used by the Hydrofogger) I also use the RO water for drinking water and making coffee, so add a couple more gallons to that total. So - I chose a fairly costly setup that includes a high capacity filter with a booster pump and a 100 gallon reservoir tank. The whole deal cost about 2K, which I can justify because it produces our drinking water as well - not to mention superior coffee (one of the major food groups!).
 
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  • #22
Just CP's. Thanks for the advice! I use ~2-3 gallons of water for the plants per week. Is it worth it?

Depends how you look at it. It will pay for itself over time. It may take a while at only 2-3 gallons per week but it will add up over time. It depends if the initial investment is worth it to wait 1-2 years for the cost to catch up for you.
 
  • #23
To me,

My RO unit was one of the best purchases I've ever made... my tap water is now somewhat over 200ppm, but since I'm in a region that burns coal for power generation we have issues with mercury etc etc. (much of which is never included in your typical water company reports)

All that aside, the convenience of having it on demand is just awesome when you are used to hauling jugs, collecting rainwater etc etc etc.

I like to keep my cp water about 20-30ppm so I don't worry about my DI stage any more, so with a typical 95% rejection ratio membrane.... I got what I need with just the membrane.

It makes the best sun tea you ever drank IMHO... Some people don't like the taste (or lack of..) of the water, I prefer it. If you have ever spent time at sea (Navy) you may recognize the taste.

RO membranes "need" to be used. You are much better off getting a smaller unit and using it more frequently that a larger unit and running it once in a blue moon.
Infrequent use can lead to bacterial issues inside the membrane, or damage to the membrane from drying out.

Just don't buy one to fill up a 55 gallon drum and use a gallon per day

If you rent, you will probably need a "portable" unit.... efficiency suffers, icemaker use is out, etc but for the renter with Cp's it's a decent option.
These have a faucet adapter much like a portable dishwasher... snap it in place, open the cold water, run the permeate line (filtered water) into your collection bucket, and run the brine (waste water) to the sink drain.

Typically you will have 3-4 gallons of brine for every one gallon of permeate

systems like this, 100-150 and try to run it at least weekly to keep the membrane from getting funky

caveat: you still need at least 45-50psig at the faucet or the system will never work well


HTH's
Av
 
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  • #24
just for ref:

Permeate: The output from the reverse osmosis membrane (the cleaned water)

Brine: The waste water output from the membrane

Brine ratio: The amount of brine compared to the amount of permeate during operation. To enable a membrane to work properly and live a long life, most of the supply water is allowed to flow across the membrane and exit out through a restrictor. This restrictor keeps some back pressure on the membrane surface.
Most membrane manufactures require a brine ratio of 3:1 to 4:1

Rejection ratio: Ratio of the measured TDS of the membrane inlet water compared to the membrane permeate outlet. Most membranes will have a listed rejection ratio of 95-98%. However, this is highly dependent on inlet pressure, inlet water temperature and pressure differential across the membrane. This is what determines when a membrane should be replaced.

If you have a brand new membrane that has a rejection ratio of 95% and your supply water has a TDS of 100ppm, the output from the membrane under ideal conditions will be 5ppm
That same system with a supply water TDS of 1000ppm will have an output of 50ppm.

To get rid of what the membrane cant, we use a "DI" (demineralization by ionization) stage, sometimes called "deionization". They are little beads that swap one ion for another, typically hydrogen for whatever the leftover bad ion is. (I'm not a chemist so I may be over simplifying it but you get the idea) These beads are typically a "consumable" product and must be replaced.

for ref, my setup:
my_rodi.jpg

my_rodi_bw.jpg


HTH's
Av
 
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  • #25
I may ask for one for Christmas.
 
  • #26
To get rid of what the membrane cant, we use a "DI" (demineralization by ionization) stage, sometimes called "deionization". They are little beads that swap one ion for another, typically hydrogen for whatever the leftover bad ion is. (I'm not a chemist so I may be over simplifying it but you get the idea) These beads are typically a "consumable" product and must be replaced.

Av

I can't think of a "gooder" explanation; though the stunning absence of a distiller in that basement leaves me saddened . . .
 
  • #27
I can't think of a "gooder" explanation; though the stunning absence of a distiller in that basement leaves me saddened . . .

shhhhhhhhhh david, you know this time of the year I use the one by my creek, creek water cools the worm better :)
 
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