When Should RO/DI cartridges be replaced?

[threebuoys]

How do you determine when to replace RO/DI cartridges?

Based on TDS rising to a certain point?

DI based on color of resin?

Any rule of thumb about how many gallons of water should be expected from a set of cartridges?

 

[Dom]

How do you determine when to replace RO/DI cartridges?

Based on TDS rising to a certain point?

DI based on color of resin?

Any rule of thumb about how many gallons of water should be expected from a set of cartridges?

When the water output TDS reading starts to rise.

You should be getting a TDS reading of ZERO on the output. As the cartridges begin to deplete, you will see TDS begin to rise.

 

[slythy]

All depends on incoming tds really. I went 5 years on my RO membranes and they were still in good working condition.

i get ~340 tds in and 8tds out. I change my sediment every couple months. Change my carbons out every couple months. Then I have 3 DI chambers. Once my first one is completly brown and my second shows a little bit of color change I replace the first one but move the second one in the first spot.

 

[FishLvR]

My Spectapure has in line and out line at every stage. I do the Sediment and carbon block every 6 months, the maxcap when it shows 1ppm usually two years, and the silica buster when I shows 1ppm. That's usually at the 3 year mark. These are both the high capacity. I change my membrane when it goes below 95% rejection. In my system that shows roughly 5ppm on the meter when coming directly from the membrane. So far that has been at the five year mark. My unit has self flushing so I flush after and before making water. I have never had my final stage above 1 ppm in the whole time I've owned the unit.

Your mileage may vary as my TDS coming in is 90ish and my psi is 80 into the house. So I get probably much longer than most. We do have sandy sediment so I HAVE to change sediment filter at 6 months or it gets too sandy.

Edited to add this is why I bought the best RODI I could. The meters have saved me tons of money, no guess work on which filter needs replacing.

 

[Randy Holmes-Farley Verified Community Expert]

I discuss many aspects of ro/di systems here:

Reverse Osmosis/Deionization Systems to Purify Tap Water for Reef Aquaria by Randy Holmes-Farley - Reefkeeping.com

 

[FishLvR]

Sometimes less is more Randy. Sometimes all people need is bad water goes in, good water comes out.

 

[dwest]

My Spectapure has in line and out line at every stage. I do the Sediment and carbon block every 6 months, the maxcap when it shows 1ppm usually two years, and the silica buster when I shows 1ppm. That's usually at the 3 year mark. These are both the high capacity. I change my membrane when it goes below 95% rejection. In my system that shows roughly 5ppm on the meter when coming directly from the membrane. So far that has been at the five year mark. My unit has self flushing so I flush after and before making water. I have never had my final stage above 1 ppm in the whole time I've owned the unit.

Your mileage may vary as my TDS coming in is 90ish and my psi is 80 into the house. So I get probably much longer than most. We do have sandy sediment so I HAVE to change sediment filter at 6 months or it gets too sandy.

Edited to add this is why I bought the best RODI I could. The meters have saved me tons of money, no guess work on which filter needs replacing.

I do this too. Very similar numbers and timing. Spectrapure all the way.

 

[Randy Holmes-Farley Verified Community Expert]

Sometimes less is more Randy. Sometimes all people need is bad water goes in, good water comes out.

Like the eco-aqualizer. lol

 

[FishLvR]

Like the eco-aqualizer. lol

LOL omg yes!

 

[FishLvR]

I do this too. Very similar numbers and timing. Spectrapure all the way.

It's legit. I mean he tests them in Phoenix water.

 

[KStatefan]

Sediment filters based on pressure drop across the filter.
Carbon filters based on gallons used compared to spec on filter for chlorine or chloromines
Membrane when rejection rate drops to a certain level I use 97%
DI resin color and/or TDS reading