Do i change the membrance?

[endlessrealm]

I have a 6 stage RODI unit by brs. And yesterday i changed the filters. And i noticed that i couldnt get the IN to be below 3. I get 3 in and out 0. And before i changed the filters i always got 1 in and 0 out.

I have a booster pump, and the automatic flush installed.

 

[StatelineReefer]

What's the TDS before all filters?

I consider it time to change the membrane when I get 97% rejection or lower. For me, that's an incoming TDS of about 280, so anything above 5 after the membrane. Anything above 0 after the DI stage and I change everything out.

 

[endlessrealm]

What's the TDS before all filters?

I consider it time to change the membrane when I get 97% rejection or lower. For me, that's an incoming TDS of about 280, so anything above 5 after the membrane. Anything above 0 after the DI stage and I change everything out.

Thats my tds just tested before the filters just my tap water

 

[StatelineReefer]

That's actually not terrible... but does indicate you should be changing your membrane now... Did it last at least 6 months?

 

[bushdoc]

97% rejection rate is arbitrary and somewhat optimistic. For human consumption you could go as low as 90-85%, but we seem to hold higher standarts for our reef tanks.
Ultimately you could go lower, to let's say 92-93%, you will be going faster through your DI resin though.

 

[endlessrealm]

That's actually not terrible... but does indicate you should be changing your membrane now... Did it last at least 6 months?

Like around a year and a half. Approximately. Its weird though why after changing the filters i get 3 and before that with dirty carbon, and membrance i get 1 in and 0 out

 

[endlessrealm]

97% rejection rate is arbitrary and somewhat optimistic. For human consumption you could go as low as 90-85%, but we seem to hold higher standarts for our reef tanks.
Ultimately you could go lower, to let's say 92-93%, you will be going faster through your DI resin though.

So the real question is do i change it or i dont change it? And why would it happen directly after installing brand new filters and not before

 

[endlessrealm]

Bump

 

[bushdoc]

I run my RO membrane to about 92% rejection rate. Your rejection rate is 96.6%.It is up to you how you run it, but new RO membranes of good quality have rejection rates of 96-99%, so your is still within acceptable limits.

 

[Uncle99]

Sometimes you need to filter and hour of water after changing any part, then retest.

Have you made a good amount of water?

 

[endlessrealm]

Sometimes you need to filter and hour of water after changing any part, then retest.

Have you made a good amount of water?

I made over 50 gallons

 

[KStatefan]

So the real question is do i change it or i dont change it? And why would it happen directly after installing brand new filters and not before

That is up to you. I would change mine if it gets below 97% rejection but my source water is 380 tds.

Same pressure at the membrane as before?

 

[endlessrealm]

That is up to you. I would change mine if it gets below 97% rejection but my source water is 380 tds.

Same pressure at the membrane as before?

Yes 80 psi. Thats why im not sure whats going on. It happened after changing my filters. Not before which is weird.