RO water filters… at the end of the changeable filter’s life…

[Magnum Man]

I’m curious about something I’ve heard several times, on this forum… that I’ve not personally witnessed with my unit… I’ve heard several people say, that the mineral content starts going up, when it’s time to change filters… I’ve not personally witnessed that, and it goes against my understanding of how filtration works… typically as a filter is used, it filters finer and finer, until nothing can pass through… so, in theory, the filtered water you get should slowly start to reduce, yet remain quality RO water, unless the pressure causes a by pass, which would be a poor design, as the pressure can’t increase more that what the water line pressure is…

I have a set of spare filters here, that I intend to put in, when the volume of filtered water no longer meets my needs… I don’t typically test my RO water every week… I don’t think there should be a need, is there???

 

[gwand]

As I understand it an RO filter efficiency doesn't necessarily decline as it ages. As the filter becomes clogged with contaminants, the water flow is restricted, leading to a decrease in GPM.

 

[Ceez]

As I understand it an RO filter efficiency doesn't necessarily decline as it ages. As the filter becomes clogged with contaminants, the water flow is restricted, leading to a decrease in GPM.

Ive had my RO unit for going on almost a year. Don't know how many gallons I've produced or have any tangible data except....when I 1st got it my tds readings were 0-2, they're now up to 14. So some of the dissolved solids are getting through now.

On another note. My water pressure is so good that my 75gpd unit is making 50g is about 8-9hrs. I'm wondering if that's too much and causing my filters to deteriorate faster? Anywhoo I'll be buying filter replacements here soon

 

[Magnum Man]

My RO unit is a low pressure unit ( for low water pressure ) and has a booster pump wired in it, to insure it meets the gps that the filter is rated for… we have a low pressure, old “stroker” pump on the Century Farm

 

[TwoTankAmin]

My understanding is that an RO membrane lasts for 2 -5 years. I also assume what it filters out, how many gallons are passed though it and the nature/quality of the input water all matter. Using prefilter modules such as carbon and sediment can helpt extend the lifeof the membrane.

MY first unit was a 3 stage RO/DI with carbon as the front stage. I replaced the carbon and RO modules once. I was prompted by the vendor to do so. The TDS had been rising before then. The last time a change was due (TDS water out was at 27 ppm) I decided to upgrade and added a sediment module in front of the carbon. When working propely I should get 0 ppm TDS out of the 4 stage for some time.

An aged or mistreated RO membrane can clog or fail to work properly. They should not be allowed to dry out once wet.

 

[Magnum Man]

Mine is a 4 stage

 

[Magnum Man]

… and to be “transparent” the 1st 6 months I was running house softener water into it… but with the flush water, I as going through salt like crazy but I suspect the salt ions rinsed out the easier than the calcium ions… so maybe making my filters last a little longer??? Still not worth it, for softener salt usage…

 

[Fishfunn]

As I understand it an RO filter efficiency doesn't necessarily decline as it ages. As the filter becomes clogged with contaminants, the water flow is restricted, leading to a decrease in GPM.

When my RO membrane starts to wear out, my TDS level at the output goes up, which puts a drain on the DI end stage to remove the excess.

I use a TDS meter that monitors the output of the RO membrane and also the output of the DI stage.

 

[hamfistUK]

When my RO membrane starts to wear out, my TDS level at the output goes up, which puts a drain on the DI end stage to remove the excess.

I use a TDS meter that monitors the output of the RO membrane and also the output of the DI stage.

This is exactly my experience as well. Mine is a 3 stage, so I simply just notice the output ppm creeping up (independent of how new the prefilter stage cartridges are). I do not notice a slowing of RO output as it ages.
I produce nearly 300 liters a week so my RO filter membrane only seems to last around 9-12 months before the ppm has crept too high for me.