RO/DI Filters: How often is too often to have to replace them?

[Privateye]

I just change them all when the color-changing DI resin changes to no blue, all brown. No schedule or analysis needed.

If the carbon was at capacity then you'd likely see increased deterioration of the resin anyway, exhausting it. It's all based on use. Different people/tanks and different RO/DI units will have different demand and capacities, so it's tough to compare one person's schedule with another imo.

 

[Spicy Reef]

I don't use RO, seems a waste of water. Two carbon blocks seem to do the trick for our water here in Seattle along with Prime

 

[PristineReef]

Depending on the TDS of your water, how much water you're making and other factors you could be replacing your RO/DI filters more often than you want to. But how often is too often? Let's poll the community today and see what others have to say!

1. How often do you have to replace your RO/DI filters?

2. What's the biggest factors that come into play in exhausting your RO/DI filters?

3. How high is your home TDS?

1. How often do you have to replace your RO/DI filters?
When my test meter show a test level. But I've learned to replace my sediment filter at least once b4 diresin is changed. It makes the diresin last longer I find.

2. What's the biggest factors that come into play in exhausting your RO/DI filters?
How dirty the water is coming into unit. Sediment filter change often to extend the life of diresin and membrane. I flush for couple minutes b4 making water and after to extend the life of membrane.

3. How high is your home TDS?
My TDS is 175 coming into unit. I do have a whole home carbon filter on all water that comes into house b4 it even hits my rodi unit. Maybe this helps I'm not sure but our water taste great

 

[Mical]

I change my sediment filter & carbon block when I see a drop in pressure, I run 90 psi normally w/booster pump. I change membranes when I see 1-2 TDS after DI resins (I run separate resins Cation, Anion & Mixed Bed). I change resins when I see color change.

 

[sghera64]

luckily I have very low TDS water before it even goes into my Rodi system. I change my filters once a year just to keep a schedule.

I stopped using DI resin years ago. All my RO water goes through Ca(OH)2 to phosphates get knocked out in that reactor before going into the tank.

My current RO membrane is going on 5 years. I use soften water with 350-600 TDS depending on time of year and what the water company is doing to their system. I will change the RO membrane if the rejection rate gets worse than 98%. After 5 years, it is still producing 95.5% rejection on the TDS meter. I credit the longevity to using soft water AND after each run, I feed the product water through for 60 seconds and I have a timer that flushes RO water through the membrane every other day.

I did a membrane autopsy when I used to feed it hard water (3 yrs was max life) and the membrane was packed with calcium and other hard water salts.

For carbon, I use 3 universal carbon block filters in series. I test them with a chlorine/chloramine test kit and change the them when there is break through. I get 12-18 months out of them. My system uses about 30 gallons per week. I think the key to carbon filter longevity is a really good sediment filter.

 

[Crotalus]

There is no set answer. Everybody's water has different levels of contaminants. I replaced Block, sediment, and membrane after a year. I use about 100 gallons a month. I replaced them when the TDS started to rise. I usually read about 7 between the membrane and the DI section. I replace the DI resin when the color changes. I make sure the TDS is zero going onto the mixing barrel and leave it at that. I extend my DI section by putting a dump valve between the membrane and DI filters and flush that way until the TDS falls. Other wise I would be putting water with a TDS of 150 or so through the resin just wasting it.

 

[NigelRichardson]

LFS mentioned that where I live (close to The centre of Melbourne, Australia) our water is “pretty good” straight out of the tap - so RODI units don’t have too many problems.

Reading the thread about other peoples TDS levels and I’m only now realising what “pretty good” means

If TDS if water going into my unit gets above 25 I think I’m having a bad day…

Its all a matter of perspective…..

 

[KWT]

As needed
Amount of water made

over 600

 

[saltyhog]

1. How often do you have to replace your RO/DI filters?

5 micron and 1 micron, every 6-8 months. Sediment filter about twice as often

2. What's the biggest factors that come into play in exhausting your RO/DI filters?

How much water I make

3. How high is your home TDS?

37-42

 

[sghera64]

I stopped using DI resin years ago. All my RO water goes through Ca(OH)2 to phosphates get knocked out in that reactor before going into the tank.

My current RO membrane is going on 5 years. I use soften water with 350-600 TDS depending on time of year and what the water company is doing to their system. I will change the RO membrane if the rejection rate gets worse than 98%. After 5 years, it is still producing 95.5% rejection on the TDS meter. I credit the longevity to using soft water AND after each run, I feed the product water through for 60 seconds and I have a timer that flushes RO water through the membrane every other day.

I did a membrane autopsy when I used to feed it hard water (3 yrs was max life) and the membrane was packed with calcium and other hard water salts.

For carbon, I use 3 universal carbon block filters in series. I test them with a chlorine/chloramine test kit and change the them when there is break through. I get 12-18 months out of them. My system uses about 30 gallons per week. I think the key to carbon filter longevity is a really good sediment filter.

I meant to write my RO unit is producing water at 99.5% rejection. When the TDS of the feed water to the RO membrane is about 500 ppm, the water leaving the RO membrane will have TDS of 2 ppm. I think I'm using SpectraPure membranes which are Dow FilmTec.

 

[BlackGoldReefs]

Depending on the TDS of your water, how much water you're making and other factors you could be replacing your RO/DI filters more often than you want to. But how often is too often? Let's poll the community today and see what others have to say!

1. How often do you have to replace your RO/DI filters?

2. What's the biggest factors that come into play in exhausting your RO/DI filters?

3. How high is your home TDS?

I honestly just purchased an R/O 4 stage unit and also upgraded it with two DI resin stages. I have not hooked it up yet, but I am concerned because my tap water is 1350-1480 on the regular. It is also treated with Chloromine. Soni am expecting the media will not last long.

 

[Ditryin]

For all the folks who are burning through DI resin...

I read a post somewhere where a guy explained how when you turn off your RO/DI the clean water in the membrane is attracted to dirty water so he suggested disconnecting it from your DI unit and flushing it before you start making water.
Since I started flushing it for about 30 seconds every time I make water, my resin colors haven't changed at all - the cation is at 100% good, my anion is at 90% good and my mixed is at 100% good and those are the same numbers I had in my notes from January. I just passed the two-year mark with my system.

Hope this helps!

 

[ying yang]

Great thread!

I change membrane every 6-8 months.
Sediment and carbon once a month or approximately every 200-250 gallons.
Idk my tap TDS.

I need to read everyone’s post, I may be going overboard!

How is everyone testing tds at each stage?
Does each stage have a T w/a shutoff valve or is everyone going through the hassle of removing the IN-Line and testing?

Hi and hello.i only have a dual inline tds meter but you can buy a triple inline tds meter so can check tds at 3 stages so guess this is how people can check ....
1,incoming tap water
2.after membrane
3.product water after di resin
If checked after sediment and carbon would have to disconnect the tds meter and place after what stage you want and check ( would have to have connectors or have longer tubing and remove a piece tubing where tds meter was while checking another place or run water into a bucket.

 

[Laith]

On my previous tank which was 250l (60g) I was changing them every six months and that was probably too often as they prefilter was always white.

In my new build the tank is 1900l (500g or so) after six months the prefilter was visibly discoloured due to the much larger volumes of water going through it.

So now I change both prefilters every three months.

The short answer is how much water you are putting through the system...

 

[Buckeye Hydro]

For all the folks who are burning through DI resin...

I read a post somewhere where a guy explained how when you turn off your RO/DI the clean water in the membrane is attracted to dirty water so he suggested disconnecting it from your DI unit and flushing it before you start making water.
Since I started flushing it for about 30 seconds every time I make water, my resin colors haven't changed at all - the cation is at 100% good, my anion is at 90% good and my mixed is at 100% good and those are the same numbers I had in my notes from January. I just passed the two-year mark with my system.

Hope this helps!

TDS Creep Bypass

At Buckeye Hydro we specialize in providing the highest quality water filtration systems and accessories for every potential need.

www.buckeyehydro.com

 

[madweazl]

We're pretty lucky to have decent water out of the tap. Typically get 0-2 TDS after the RO membrane and the DI resin lasts at least 6 months (8-9 typically) doing weekly, 22-25g water changes on our 150g.

 

[piranhaman00]

I change sediment and carbon every 6-8 months depending on how brown sediment gets. I am on city water but no chloramines and below 0.5ppm chlorine so I do not worry about carbon filters fouling.

200ppm tds incoming, 3-4 out of membrane , with cold water , when I need water fast I use 90F water and produce 4x speed but incoming around 300 and 6-10 out of membrane. Burn through resin

 

[Big Smelly fish]

So set time, depends on my output tds of the membrane and after the di filters. I have valve on every line and it keep water in unit so they are always wet. The membrane last for a few years or longer and everything else replaced as needed.

 

[killr66tb]

Membrane is yearly, carbon is every six months and the sedement is every month. My tap TDS is 450

That's is illegal

 

[SKEETER1978]

Sounds like you should have 2X chambers of anion (blue), and 1 chamber of mixed bed. You'd have to change less often, and the mixed bed should have more than enough cation sounds like. Just a thought.

not a bad idea! Im going to try that... Thanks