RODI QUESTION

[gwand]

I plumbed in a RODI system on February 1, 2026. At what ppm or ecs should I change the cartridge. My well water is 550 ppm, very high. So the system will clog faster than most.

 

[seangee]

I use RO only (replaced the DI cart with a carbon post filter). My tap water is around 450ppm, and 4-6 with fresh filters. I usually change my cartidges when it gets to to 20 ppm - usually 6 - 9 months. My current membrane is 2 years old and still good. The system has an auto back flush system which suppposedly makes the membrane last longer. I'll change it when I no longer get below 10 with fresh filters.
FWIW I ditched the DI part because I was having to replace the resin monthly to keep it at 0 - simply not neccessary for tropical fish.

 

[bgarthe]

Get a Whole House Filter to filter water prior to getting to your RO.
Install the extra large 2’ prefilters (tubular set) for the RO. I usually change mine out when I notice reduced flow or abt every 18 mos or so.

 

[anewbie]

The biggest issue will be the carbon - and it should have a gallon rating. If you don't replace the carbon the chlorine (if your area has chlorine) will tear up the ro membrane. The issue for the di/ro membrane is more by gallon than time. di in truth doesn't last very long - i get 5 tds without di and di only last a few days for me so i gave up on di. My ro membrane had to be replaced around the 100,000 gallon mark - i have it written down - i noticed the tds going up to past 10 - NOTE: temperature and pressure will impact the effectiveness of the ro membrane so a rise will not immediately mean the membrane is exhasuted. Also some units backflush (mine does but i suspect yours does not but you can get a backflush thingy from bulkreef - it will extend the life of the membrane).

For carbon i use some million gallon prefilter with carbon (you can find them pretty easy - sort of like whole house soft-ner but just carbon.

A whoile house softner depending on the type will convert minerals to salt but this salt is left in the water increasing the sodium level if you drink it the ro member will filter it out.

 

[Back in the fold]

I change my sediment and carbon pre-filters on my R/O unit every three months . Chlorine is the biggest culprit in short lifespans of R/O membranes . I replace my membrane every year whether it needs it or not . As @bgarthe noted , and this is something I’d like to do , install a whole house filter . That would lessen the chlorine even more before it hits your R/O unit .
It’s spring runoff time here on The Mighty Yellowstone River and my water is reading 1 PPM today . You read that right ONE PPM !

 

[anewbie]

I change my sediment and carbon pre-filters on my R/O unit every three months . Chlorine is the biggest culprit in short lifespans of R/O membranes . I replace my membrane every year whether it needs it or not . As @bgarthe noted , and this is something I’d like to do , install a whole house filter . That would lessen the chlorine even more before it hits your R/O unit .
It’s spring runoff time here on The Mighty Yellowstone River and my water is reading 1 PPM today . You read that right ONE PPM !

1ppm of what ? Nitrite ? That's pretty deadly.

 

[Back in the fold]

1ppm of what ? Nitrite ? That's pretty deadly.

Total Dissolved Solids .

 

[anewbie]

Total Dissolved Solids .

Well... obviously your local Moose population is not doing their proper thing in the rivers.

 

[Back in the fold]

Well... obviously your local Moose population is not doing their proper thing in the rivers.

The Mighty Yellowstone River , one of the last wild un-dammed rivers in The American West , is wholly fed by runoff from mountain snowpack . That’s just about pure distilled water going into it . It’s coming out of my tap today at 62 PPM TDS . We don’t drink moose piss around here .

 

[anewbie]

The Mighty Yellowstone River , one of the last wild un-dammed rivers in The American West , is wholly fed by runoff from mountain snowpack . That’s just about pure distilled water going into it . It’s coming out of my tap today at 62 PPM TDS . We don’t drink moose piss around here .

The things people don't know they are doing

Oh well the only real problem with stone that is yellow is you have to ask where has it been

Now i could talk about dogs and snow but i suppose i should save that for another thread.

 

[Back in the fold]

The things people don't know they are doing

Oh well the only real problem with stone that is yellow is you have to ask where has it been

Now i could talk about dogs and snow but i suppose i should save that for another thread.

Yeah , that’s funny . The Yellowstone River is so named because French fur trappers in the very early days of the old fur trade called it the Roche Juane ( sic ? ) or yellow stone because of the color of the rocks on the bottom they saw . The Appsalooke tribe ( Crows ) call it , as it’s translated into English , The Elk River but their native language calls it something else that I can’t pronounce but sounds very elegant . I really have to apply myself to learning how to pronounce and spell that . This is an area rich in history and really not so long in the past . General Custer got fitted for his Arrow shirt only 40 miles from where I live .

 

[gwand]

I change my sediment and carbon pre-filters on my R/O unit every three months . Chlorine is the biggest culprit in short lifespans of R/O membranes . I replace my membrane every year whether it needs it or not . As @bgarthe noted , and this is something I’d like to do , install a whole house filter . That would lessen the chlorine even more before it hits your R/O unit .
It’s spring runoff time here on The Mighty Yellowstone River and my water is reading 1 PPM today . You read that right ONE PPM !

In what form does chlorine take in well water? As sodium chloride or some other molecule?

 

[anewbie]

In what form does chlorine take in well water? As sodium chloride or some other molecule?

Is it your local well in your backyard - then it depends if you add it or not - a lot of home owners don't add chlorine.

 

[gwand]

Is it your local well in your backyard - then it depends if you add it or not - a lot of home owners don't add chlorine.

Yes. The well is in my backyard. We don’t add chlorine. So I assume there is no significant level of chlorine or for that matter chloride in my well water. But the well water TDS is around 550 ppm. So my RODI system has a lot of work to do.

 

[anewbie]

You should occasionally get your well water tested for minerals and bacteria et all. I'm purchasing a property with a well and going through the steps.