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

[LeftyReefer]

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. I just got my 100GPD RO/DI system from the Marine Depot liquidation sale... so I've only had it a couple weeks, so no idea how long before I will need to change out the filters yet.

2. see above

3. 95 TDS (measured today)

I have the triple in-line TDS meter. #1 measures my tap, #2 measures TDS out of the RO and #3 measures TDS out of the DI (final stage).

So knowing the TAP TDS and the TDS out of the RO, I can tell what the rejection rate is and will replace when it drops below what I find acceptable. I wll change my DI resin when I get anything other than 0 TDS out of it. I bought several sets of filters during the MD sale while they were cheap, so I should be set for a while.

Really enjoying making my own RODI water now. sure as heck beats lugging water from Walmart or the LFS.

 

[StewL6]

I have terrible town water reading on inline TDS meter of around 550 or more sometimes.

I run two 5 micron Carbon Block cartridges in Big Blue canisters on my whole house filter on my main water line into house. I change the carbon block cartridges every three months.

Then my RO/DI unit is feed off off my main water in line. I get down to 6 or 7 TSD RO out. I just like last week upgraded to two DI cartridges. I usually make 20 gallons of SW a week but my Son has a 75 gallon new build that has running for 2 months and I have a 110 gallon new build about 2 weeks away from first water so expect to be making a lot more SW to support the 2 larger tanks and three ~30 gallon nano tanks. 28 JBJ about 8 years old.

My RO unit is over 8 years old and I changed the RO unit filter cartridges and membranes last year. Was still making water volume but was around 21 TSD out figured it was time.

Was fun.

 

[Homebrewer]

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’d like to see this re-polled based on gallons made, not time. Then if the member posts the source TDS, readers could cross the source TDS vs “gallons before replacement” and it would allow a crude estimate of how frequent certain components should be replaced.

Time seems the wrong measure for the poll. Just my opinion.

 

[Treefer32]

Given that my TDS out of my RO unit is at most 5 - 8 I would guess tap water is around 200-300. I do run all my water through the water softener first, then to the RODI unit. I replace my sediment filters once a year and RO membranes once every 5-6 years. I have a 5 gallon pressurized holding tank for my homes water. It feeds the ice maker and water for the fridge, icemaker in the basement bar, and water spouts for drinking in the kitchen and basement bar. I use it for all my cooking etc. So, it gets used a lot.

On top of that I use it to store 75 gallons of RODI for my ATO. Which I go through in about a month or so. And then water changes, I do around 130 gallons of water changes a month (I have been in the past, may stop now).

DI Resin, I change every 3 months when I start registering 1 TDS out of the DI side.

So, around 200 gallons a month is what I go through of RODI. Plus another probably 90-100 gallons a month of just general drinking water and ice, etc for 3 people.

I keep in mind that the water is softened first. And I've noticed it's really soft right now just from the shower water. Takes ten minutes to wash the shampoo out of hair. I would think salt vs. other hard minerals is easier on filters. But, that's another discussion.

I probably should change them more often, I just don't. . .

 

[Buckeye Hydro]

I’d like to see this re-polled based on gallons made, not time. Then if the member posts the source TDS, readers could cross the source TDS vs “gallons before replacement” and it would allow a crude estimate of how frequent certain components should be replaced.

Time seems the wrong measure for the poll. Just my opinion.

Remember that the sediment filter and carbon block(s) DO NOT remove TDS. The sediment filter is used to remove UNdissolved solids. So the TDS reading really has nothing to do with how often you should change your prefilters. Nearly all of the TDS is removed by the membrane, and the DI polishes up the last few percent that remains in the permeate.

 

[Homebrewer]

Remember that the sediment filter and carbon block(s) DO NOT remove TDS. The sediment filter is used to remove UNdissolved solids. So the TDS reading really has nothing to do with how often you should change your prefilters. Nearly all of the TDS is removed by the membrane, and the DI polishes up the last few percent that remains in the permeate.

Fair point. My issue is with having the poll relate to time vs. use. “How often” should relate to the life of the filters relative to how much they’ve filtered, not by how old they are, which is how the poll is set up.

 

[Buckeye Hydro]

Fair point. My issue is with having the poll relate to time vs. use. “How often” should relate to the life of the filters relative to how much they’ve filtered, not by how old they are, which is how the poll is set up.

Understood. Amount of use is a fair metric when evaluating the life of the carbon block - shoot for about 50% of the chlorine capacity of the block.

That metric won't help at all with the sediment filter however... because
* the amount and size of the sediment (the "sediment profile") in tap water varies wildly across the country, and
* often varies significantly by water source (residential well vs municipal water), and
* people use sediment filters with different pore sizes.

We often tell people that dialing in the perfect sediment filtration for their particular application and source water (if they're interested in such a thing) will take a bit of experimentation. The good thing here is that sediment filters are inexpensive.

Russ

 

[Homebrewer]

Understood. Amount of use is a fair metric when evaluating the life of the carbon block - shoot for about 50% of the chlorine capacity of the block.

That metric won't help at all with the sediment filter however... because
* the amount and size of the sediment (the "sediment profile") in tap water varies wildly across the country, and
* often varies significantly by water source (residential well vs municipal water), and
* people use sediment filters with different pore sizes.

We often tell people that dialing in the perfect sediment filtration for their particular application and source water (if they're interested in such a thing) will take a bit of experimentation. The good thing here is that sediment filters are inexpensive.

Russ

Good stuff here. Thanks for pointing all that out.

Obviously there’s a lot more that goes into the decision of when to replace, certainly more than how much time passes between changes… which was kind of the point I was trying to make.

Appreciate the dialogue.