RO Question...

[Timbits]

I installed my new RO/DI filter about a year ago... still haven't changed the filters on the thing. Just checked my TDS and it's reading at 1. That seems pretty low still... does that mean my filters are still good? I've read that you have to replace filters every 6 months or something but my TDS has been reading 0 for a long time until recently it's reading 1.

Not really sure when i should change the filters. Just wanna make sure the water comming out is still good. Can someone pls help?

Thanks in advance.

Tim

[BlueTang<3]

How much water have you made? I have read that the pre and carbon filters should be changed at 6 months as bacteria can grow in them, but ro membrane can go a few years. I usually change my di resin when it moves from 0. Is you tds meter calibrated?

[Timbits]

Originally Posted by BlueTang<3

How much water have you made? I have read that the pre and carbon filters should be changed at 6 months as bacteria can grow in them, but ro membrane can go a few years. I usually change my di resin when it moves from 0. Is you tds meter calibrated?

im not really sure... maybe around 1000 gallons... is that a lot? i believe it is calibrated...

[BlueTang<3]

Yeah if you got 1000 from your ro thats good, I would say if your not noticing any changes in your tank let it go.. But then again a filter change and di resin change is only 28 bucks

[Timbits]

Originally Posted by BlueTang<3

Yeah if you got 1000 from your ro thats good, I would say if your not noticing any changes in your tank let it go.. But then again a filter change and di resin change is only 28 bucks

k thx i think i might change it .. a year seems pretty long lol

anyone from Vancouver can chime in? as our water supply would probably be the closest. How often do you change your filters?

[mike31154]

Vernon, not Vancouver, but I have a few thoughts on RODI systems & filter life. My 75 gpd has been running for well over two years and I've been keeping track of throughput in gallons since day one on an Excel spreadsheet (along with a bunch of other tank related paramaters). Only thing I've changed so far is the first stage 5 micron sediment filter. This seems to get fouled up after about every 100 gallons of pure water produced. Assuming a 1 to 4 good to waste water ratio, that's approximately 500 gallons of water through the filters (100 good, 400 waste).

After a year of use, I reconfigured the system somewhat as well. It came with a 5 micron prefilter, refillable granulated carbon stage, 0.5 micron carbon block, 75 gpd membrane & colour changing DI stage. After some research I realized that two carbon stages are overkill in my case since my source water is treated with chlorine, not chloramine. General consensus is that water treated with chloramine requires two carbon stages to protect the RO membrane. Chlorine treated water only requires one good quality carbon stage. So I pulled the refillable granular carbon stage & replaced it with a 1 micron poly filter.

From April 2009 to now, I've produced just over 2,000 gallons of pure water. Using the same good to waste ratio, that's about 10,000 gallons total throughput. The MAXCL carbon block on my system is rated to remove chlorine for up to 20,000 gallons, so it should be good for at least another year. It would be foolish to replace that at a 6 month interval without knowing how much water I've put through it. To be on the safe side, a month ago I tested the water after the carbon filter for chlorine & it was negative. TDS after the DI stage is still 0.

I've seen a number of threads that indicate you guys on the west coast are fortunate to have some of the lowest TDS source water anywhere, something like 10 to 20 TDS. Compare that to my source TDS in the 210 to 220 range here in Vernon. You haven't provided many details on the type of system you have other than that your TDS is now at 1 vs the 0 it's been for the past year. TDS of 1 isn't that bad, but it is an indicator that something needs to be looked at and a bit unusual compared to the performance of my system which is presumably dealing with much higher input TDS.

Any idea what your water pressure is? I have two pressure guages installed and use them to determine when my pre filter needs service. Once the pressure differential between the two guages rises from about 20 psi to 24, I know it's time to change stage one. It's also quite obvious from the colour of the filter, no longer the pristine white it was when new. You might also want to periodically check or keep track of the source water TDS. It can change seasonally or if the city decides to flush some of the water mains. This could drive up the source water TDS and also your RODI output. A few more details on your particular system will help with regard to troubleshooting any possible issues.

[StirCrazy]

Originally Posted by Timbits

I installed my new RO/DI filter about a year ago... still haven't changed the filters on the thing. Just checked my TDS and it's reading at 1. That seems pretty low still... does that mean my filters are still good? I've read that you have to replace filters every 6 months or something but my TDS has been reading 0 for a long time until recently it's reading 1.

Not really sure when i should change the filters. Just wanna make sure the water comming out is still good. Can someone pls help?

Thanks in advance.

Tim

in reality down on the coast you should be chainging out prefilter more than normal. this is due to the warmer weather and algae content in water supplys. I know in victoria I was changing out my first filter every 3 months during the summer and 4 or 5 months in the winter. I switched my first filter to a 25 to 1 micron absolute filter that I added on and this made my carbon filters last much longer.


if you have had a 0 ppm output for a long time and now your getting one then something has changed, start with your filters as generaly ppm of supply water spikes in the spring not in the fall.

Steve