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Trashcan-sized RO filters that you can install at home always felt like magic, yet I strongly feel they should be a commodity in the developed world, something

Trashcan-sized RO filters that you can install at home always felt like magic, yet I strongly feel they should be a commodity in the developed world, something you'd expect out of wherever you live, just like stable AC power. A friend used to be a salesman for those; they'd bring an electrolysis device to a presentation at your home, and show what kind of stuff was floating in your tap water. It made for a cool show but also did help spread awareness of just how bad the water was.

toast0 3y ago
Aren't they a commodity? You can stop by any hardware store and grab a system and a bag of salt. Not much need to consider brand names, they more or less work the same. Edit to add: Apparently I'm easily confused. I thought water softening was happening by reverse osmosis, but it's a different mechanism.
- zbrozek 3y ago
  That's not a reverse osmosis system, but a water softener that swaps ions like calcium with ions like potassium or sodium.
  - elil17 3y ago
    Most RO systems have multiple layers, including a water softener.
    - abfan1127 3y ago
      all RO systems I've found have a carbon filters, sediment (paper) filters and perhaps a VOC (carbon) filter. I've never seen a salt-based water softener stage for a home RO system.
      - BugsJustFindMe 3y ago
        In RO context it's called remineralization (or alkalinization, I guess), not softening, and a lot of home RO systems have a final stage for it. Googling for reverse osmosis minerals will bring you to a large number of probably fabricated claims about water pH and health that ultimately align on taste preference. > “Remineralization is typically to enhance the flavor of the water, because reverse osmosis reduces the level of minerals in the water significantly, and some consumers prefer the taste of the water when there is enhanced mineral content,” explains Rick Andrews, of the National Sanitation Foundation’s Global Water Program. - https://www.thespruce.com/best-reverse-osmosis-systems-4586893 https://www.thespruce.com/best-reverse-osmosis-systems-45868... https://www.homedepot.com/p/ISPRING-Premium-10-in-Universal-Inline-Alkaline-Replacement-Water-Filter-Cartridge-for-Reverse-Osmosis-RO-System-pH-FA15US/314242804 https://www.homedepot.com/p/ISPRING-Premium-10-in-Universal-... https://www.homedepot.com/p/Express-Water-Alkaline-Water-Filter-Replacement-Mineral-Antioxidant-pH-Under-Sink-and-Reverse-Osmosis-System-FLTALK10Q-1PK/307563269 https://www.homedepot.com/p/Express-Water-Alkaline-Water-Fil... https://thewatergeeks.com/how-to-remineralize-ro-water/ https://thewatergeeks.com/how-to-remineralize-ro-water/ etc
      - mythrwy 3y ago
        It depends on how hard your water is, but if it's very hard and the RO system gets lots of use, you need a softener or anti-scalant injector that injects a small amount of chemical which prevents scale buildup. If you don't do this and have particularly hard water the membranes foul pretty rapidly. In the case of undersink systems pumping out two gallons or so a day from standard municipal water, it's probably less important. I only know this because I've been playing with osmosis systems for a few years and have built one that does around 150 gallons a day from undersink system parts with 2 membranes, some filters and pumps for my garden (otherwise my water is simply too hard to grow all the things I want to grow).
kibwen 3y ago
There's no free lunch here. Typical reverse osmosis filters produce one unit of clean water for every three units of intake, functionally tripling the cost of water (not including the price of the filters themselves, which should be replaced annually).
- whoisburbansky 3y ago
  Wait, where do the other two units of water go?
  - kibwen 3y ago
    Ideally into your sewage system, as they are now concentrated wastewater (although if you live in a developed region with centralized water treatment, there won't be that much waste in the water to begin with). RO systems designed for processing seawater have a much harder time of it, as their waste is ultra-salty brine which will kill any local marine ecosystems if you decide to just dump it back into the sea.
    - kurthr 3y ago
      Since the flow of deionized water is only 1/10 of total water flow... I think the increase in "waste" concentration is also only about 10% even of the filtered water is perfectly pure. So if you had 400ppm total dissolved solids it would now be *10/9=444ppm. Not much of a concern.
    - gnicholas 3y ago
      That would not be ideal for me (Bay Area resident) where water is crazy expensive. I'd want to keep it for watering plants, flushing toilets, etc.
      - seanp2k2 3y ago
        Yes, the only problem is that most homes are not plumbed for grey water and it's a very expensive retrofit. If you're building a new home, ask about that and structured wiring. It's unfortunately usually a way more economical idea to just get those toilets that have a sink built into the top (popular in countries like Japan) that use the hand washing water to flush the toilet vs trying to store and/or pump it around.
whatshisface 3y ago
What would electrolysis reveal about your tap water? That is not a normal test for water quality. What happened to the water when the machine was turned on?
- rollcat 3y ago
  https://www.youtube.com/results?search_query=tap+water+electrolysis https://www.youtube.com/results?search_query=tap+water+elect...
  - whatshisface 3y ago
    So... it's a scam where they put iron from the electrodes into the water, then show you the discoloration?
    - rollcat 3y ago
      I don't understand the physics, but as I said, it was a cool show.
m463 3y ago
> Trashcan-sized RO filters I think the RO filter is still a small cartridge, the thing that looks like a white bbq propane tank is just a water reservoir since the filtering is very slow.

toast0 3y ago

Aren't they a commodity? You can stop by any hardware store and grab a system and a bag of salt. Not much need to consider brand names, they more or less work the same. Edit to add: Apparently I'm easily confused. I thought water softening was happening by reverse osmosis, but it's a different mechanism.

zbrozek 3y ago
That's not a reverse osmosis system, but a water softener that swaps ions like calcium with ions like potassium or sodium.
- elil17 3y ago
  Most RO systems have multiple layers, including a water softener.
  - abfan1127 3y ago
    all RO systems I've found have a carbon filters, sediment (paper) filters and perhaps a VOC (carbon) filter. I've never seen a salt-based water softener stage for a home RO system.
    - BugsJustFindMe 3y ago
      In RO context it's called remineralization (or alkalinization, I guess), not softening, and a lot of home RO systems have a final stage for it. Googling for reverse osmosis minerals will bring you to a large number of probably fabricated claims about water pH and health that ultimately align on taste preference. > “Remineralization is typically to enhance the flavor of the water, because reverse osmosis reduces the level of minerals in the water significantly, and some consumers prefer the taste of the water when there is enhanced mineral content,” explains Rick Andrews, of the National Sanitation Foundation’s Global Water Program. - https://www.thespruce.com/best-reverse-osmosis-systems-4586893 https://www.thespruce.com/best-reverse-osmosis-systems-45868... https://www.homedepot.com/p/ISPRING-Premium-10-in-Universal-Inline-Alkaline-Replacement-Water-Filter-Cartridge-for-Reverse-Osmosis-RO-System-pH-FA15US/314242804 https://www.homedepot.com/p/ISPRING-Premium-10-in-Universal-... https://www.homedepot.com/p/Express-Water-Alkaline-Water-Filter-Replacement-Mineral-Antioxidant-pH-Under-Sink-and-Reverse-Osmosis-System-FLTALK10Q-1PK/307563269 https://www.homedepot.com/p/Express-Water-Alkaline-Water-Fil... https://thewatergeeks.com/how-to-remineralize-ro-water/ https://thewatergeeks.com/how-to-remineralize-ro-water/ etc
    - mythrwy 3y ago
      It depends on how hard your water is, but if it's very hard and the RO system gets lots of use, you need a softener or anti-scalant injector that injects a small amount of chemical which prevents scale buildup. If you don't do this and have particularly hard water the membranes foul pretty rapidly. In the case of undersink systems pumping out two gallons or so a day from standard municipal water, it's probably less important. I only know this because I've been playing with osmosis systems for a few years and have built one that does around 150 gallons a day from undersink system parts with 2 membranes, some filters and pumps for my garden (otherwise my water is simply too hard to grow all the things I want to grow).

kibwen 3y ago

There's no free lunch here. Typical reverse osmosis filters produce one unit of clean water for every three units of intake, functionally tripling the cost of water (not including the price of the filters themselves, which should be replaced annually).

whoisburbansky 3y ago
Wait, where do the other two units of water go?
- kibwen 3y ago
  Ideally into your sewage system, as they are now concentrated wastewater (although if you live in a developed region with centralized water treatment, there won't be that much waste in the water to begin with). RO systems designed for processing seawater have a much harder time of it, as their waste is ultra-salty brine which will kill any local marine ecosystems if you decide to just dump it back into the sea.
  - kurthr 3y ago
    Since the flow of deionized water is only 1/10 of total water flow... I think the increase in "waste" concentration is also only about 10% even of the filtered water is perfectly pure. So if you had 400ppm total dissolved solids it would now be *10/9=444ppm. Not much of a concern.
  - gnicholas 3y ago
    That would not be ideal for me (Bay Area resident) where water is crazy expensive. I'd want to keep it for watering plants, flushing toilets, etc.
    - seanp2k2 3y ago
      Yes, the only problem is that most homes are not plumbed for grey water and it's a very expensive retrofit. If you're building a new home, ask about that and structured wiring. It's unfortunately usually a way more economical idea to just get those toilets that have a sink built into the top (popular in countries like Japan) that use the hand washing water to flush the toilet vs trying to store and/or pump it around.

whatshisface 3y ago

What would electrolysis reveal about your tap water? That is not a normal test for water quality. What happened to the water when the machine was turned on?

rollcat 3y ago
https://www.youtube.com/results?search_query=tap+water+electrolysis https://www.youtube.com/results?search_query=tap+water+elect...
- whatshisface 3y ago
  So... it's a scam where they put iron from the electrodes into the water, then show you the discoloration?
  - rollcat 3y ago
    I don't understand the physics, but as I said, it was a cool show.

m463 3y ago

> Trashcan-sized RO filters I think the RO filter is still a small cartridge, the thing that looks like a white bbq propane tank is just a water reservoir since the filtering is very slow.