Sudden increase in TDS levels......reason?

[Emma01]

What would cause a sudden increase in TDS levels? The filters/canisters of the RO are only a week old and not used much yet, and the DI pod installed 2 days ago.
Yesterday my levels were
Pre DI- 2 Post DI - 0
Today
Pre DI- 5 Post DI- 2
Is there a filter/membrane exhausted already? I have flushed the system, which didn’t make a difference.
Thanks
Emma

 

[laverda]

It is hard to say without more information. Water supplies from the city change often which my be the cause. I know for a while my water supply had a lot of CO2 which was depleting my DI very rapidly. Do you know what your TDS is from the tap it may have increased which could account for the higher TDS out of your membrane. Again my tap water varies from around 300 to almost 400, causing the TDS out of my membranes to change. If the TDS out of your membrane continues to climb the membrane may be bad. Tempature and water pressure also affect how well the membrane works. You DI should be reducing it to zero no mater the input if it is working properly. Since your DI is only 2 days old, I would double check you DI canister to make sure some of your water is not bypassing the resin some how.

 

[Water Dog]

Could it be TDS creep? After measuring the post RO - 5 and post DI - 2 did you run it for a while and see if the post RO settled down back to 2?

When initially restarting my RODI unit, I use a 3 way valve to divert high TDS (TDS creep water) to the drain thereby bypassing the DI stage. After the TDS creep water is flushed out, I then flip the lever on the 3 way valve and route the water back to the DI stage. This will dramatically increase the life of your DI resin.

Here is a 3 way valve...

https://www.bulkreefsupply.com/3-way-ball-valve-with-john-guest-1-4-push-connect.html

Here’s a great video by @Flippers4pups about TDS creep...

 

[Water Dog]

Also, here’s a good discussion about TDS creep. Read post #8 by @AZDesertRat. He does a great job of explaining what TDS creep is and how to work around it to prolong DI resin life.

https://www.reef2reef.com/threads/tds-creep-help.171329/

 

[Emma01]

It is hard to say without more information. Water supplies from the city change often which my be the cause. I know for a while my water supply had a lot of CO2 which was depleting my DI very rapidly. Do you know what your TDS is from the tap it may have increased which could account for the higher TDS out of your membrane. Again my tap water varies from around 300 to almost 400, causing the TDS out of my membranes to change. If the TDS out of your membrane continues to climb the membrane may be bad. Tempature and water pressure also affect how well the membrane works. You DI should be reducing it to zero no mater the input if it is working properly. Since your DI is only 2 days old, I would double check you DI canister to make sure some of your water is not bypassing the resin some how.

I set up the RO/DI in an outside shed that had old pipe work, that had been unused for MANY years.
It’s impossible to put inside house due to space.
I’m beginning to wonder that I when I set up the RO/DI and let it run for a good 48 hours, have the filters quickly become exhausted due to the old pipe work and not using the pipes. The Filter is visibility brown already. Could it just be that it’s got rid of all the ‘stuff’ in the old pipes. And by me replacing the filters/DI resin now, might this solve my TDS problem??
Thanks
Emma

 

[laverda]

That is very possible. I would run some more water through the pipe full blast to help clean it out more before hooking back up to you RO/DI unit. the water flow through it is pretty slow so I doubt it cleaned it all out yet.

 

[Emma01]

That is very possible. I would run some more water through the pipe full blast to help clean it out more before hooking back up to you RO/DI unit. the water flow through it is pretty slow so I doubt it cleaned it all out yet.

Thanks I’ll give flushing it for a day and see what happens. Thanks