Rodi question

[jdpeters]

When flushing out my RO membrane today I couldn’t get the read out lower than 2ppm, is it possible that it’s time to change the RO membrane? Also, any tips to know when the best time to replace di resin?
Thanks!

 

[Gumbies R Us]

How long have you had the RO unit?

This thread should help you out!
https://www.reef2reef.com/threads/when-to-change-ro-di-membrane-and-di-cartridges.955133/

 

[GSPClown94]

Is that 2 ppm after the RO membrane and before DI or 2 ppm after DI?

 

[jdpeters]

How long have you had the RO unit?

This thread should help you out!
https://www.reef2reef.com/threads/when-to-change-ro-di-membrane-and-di-cartridges.955133/

Oh nearly 10 years but I replaced all the stages a year ago when I got back into hobby. I only have a 40b but recently have made a bunch of water because I’m getting another system started roughly the same size.

I will check that article out, thank you for the reference

 

[jdpeters]

Is that 2 ppm after the RO membrane and before DI or 2 ppm after DI?

2ppm before the di resin. I have pretty good source water I believe, it’s a combo of mountain river runoff and well.

 

[GSPClown94]

2ppm before the di resin. I have pretty good source water I believe, it’s a combo of mountain river runoff and well.

That's way better than what I'm getting after my RO. I think your RO membrane is probably fine. RO membranes have a listed rejection rate at some optimal pressure and temperature from the manufacture. For example 99% at 60 psi and 77F. You could check TDS before and after RO and compare to the specs of your membrane if you want but 2 ppm after RO sounds pretty good to me.

 

[KStatefan]

2ppm before the di resin. I have pretty good source water I believe, it’s a combo of mountain river runoff and well.

When you are flushing a membrane you are flushing the "dirty" side of the membrane only. It is not designed to get the permeate side to a zero TDS.

 

[jdpeters]

2ppm before the di resin. I have pretty good source water I believe, it’s a combo of mountain river runoff and well.

When you are flushing a membrane you are flushing the "dirty" side of the membrane only. It is not designed to get the permeate side to a zero TDS.

Ok. I guess it’s worth noting that before I could flush it down to 1 tds within 3-4 minutes but after 15 I could only get it down to 2

 

[jdpeters]

So I noticed my psi is down to 55 now, should I consider changing out my sediment and carbon filter?

 

[BryanM]

So I noticed my psi is down to 55 now, should I consider changing out my sediment and carbon filter?

I rarely if ever measure tds of the flushed water, only the water I'm making, so I can't help there.

Drops in pressure usually indicate needing to replace sediment filter.

Most people use color changing DI resin, so when the color is nearly all gone (in my case turns yellow from blue/black), its time to change.

I found some reads that indicate that cation and anion are usually consumed in wildly different amounts, and that is try in my case. So I have switched those out into separate canisters, and have changed the one that depletes faster 3x already without touching the other side.

 

[jdpeters]

So I noticed my psi is down to 55 now, should I consider changing out my sediment and carbon filter?

I rarely if ever measure tds of the flushed water, only the water I'm making, so I can't help there.

Drops in pressure usually indicate needing to replace sediment filter.

Most people use color changing DI resin, so when the color is nearly all gone (in my case turns yellow from blue/black), its time to change.

I found some reads that indicate that cation and anion are usually consumed in wildly different amounts, and that is try in my case. So I have switched those out into separate canisters, and have changed the one that depletes faster 3x already without touching the other side.

It’s been nearly a year. Fortunately swapping out filters is pretty economical and a worthwhile investment