ppm on ro/di filter

[stevercleeze]

what would you think is the cut off point of ppm of the ro /di water before replacing filters. my reading is up to 4ppm. chicago water here

 

[disc1]

I replace DI when it gets above 1. I do the RO membrane when the water before the DI gets into the teens.

 

[stevercleeze]

seems a little extreme changing an expensive filter at a 1

 

[disc1]

Don't like phosphate in my water. Plus that's only about once a year or so for me. My water is extremely good out of the tap and I have a high rejection membrane.

 

[disc1]

Besides, once DI is exhausted it can start to leech things back into the water as it exchanges larger softer ions for smaller harder ones.

 

[stevercleeze]

so then does that mean that a 1 is on the verge of leeching toxins back into the water?

 

[disc1]

If there is any TDS in the water then the DI is likely exhausted. Some of it comes with an indicator that changes color, but sometimes the resin gets channels in it and the outside part you see doesn't change right. Once it is exhausted, one of the first things to come off is phosphate.

 

[Toddrtrex]

Your pre-filter and carbon should be changed every 6 months -- at most. I personally change mine around 3-4 months, whenever the pressure starts to drop.

The DI resin should be changed/ordered whenever the TDS gets above 1.

The RO membrane is a bit (( though not all that much )) more complex. First you should know the rejection rate of your membrane (( mine happens to have a 96-98% rejection rate )), the tap water TDS, and finally the post RO (( but before the DI resin )) TDS.
Once the rejection rate is less then the stated rate, it is time to change the membrane -- should expect 2-3 years, with average TDS.

An example, if my TDS (( tap )) was 100, and the post RO was above 5, that would give me a rejection rate of 95%; at that point I would order a new membrane.

For me (( at least at my old place, haven't tested the new place yet, but it is still Lake Michigan water )) I have a starting TDS of 155. My RO membrane was 3 years old when I last replaced it, and the DI resin was about 9 months old; I wasn't schedule to replace it, but I wasn't aware that they were going to do work on the pipes, and it trashed my membrane/resin.

 

[reefsahoy]

I put 2 di filters in series and when the second filter begins to change color I replace the first filter then swap the order to make the new filter the second filter. This way I waste very little di media.

 

[evsalty]

Your pre-filter and carbon should be changed every 6 months -- at most. I personally change mine around 3-4 months, whenever the pressure starts to drop.

The DI resin should be changed/ordered whenever the TDS gets above 1.

The RO membrane is a bit (( though not all that much )) more complex. First you should know the rejection rate of your membrane (( mine happens to have a 96-98% rejection rate )), the tap water TDS, and finally the post RO (( but before the DI resin )) TDS.
Once the rejection rate is less then the stated rate, it is time to change the membrane -- should expect 2-3 years, with average TDS.

An example, if my TDS (( tap )) was 100, and the post RO was above 5, that would give me a rejection rate of 95%; at that point I would order a new membrane.

For me (( at least at my old place, haven't tested the new place yet, but it is still Lake Michigan water )) I have a starting TDS of 155. My RO membrane was 3 years old when I last replaced it, and the DI resin was about 9 months old; I wasn't schedule to replace it, but I wasn't aware that they were going to do work on the pipes, and it trashed my membrane/resin.

+.75 lol

I left out .25 because to me the DI reading shouls ALWAYS be ZERO. That is the point of the DI stage. I change mine WHEN I see 1 TDS.

This is what the filterguys say about it which matches what Spectrapure says as well.

Originally Posted by Thefilterguys
DI is on an as needed basis and you always want to see zero tds and change as soon as you see a reading above zero. The tds reading you see in the begining is called tds creep off the membrane and is normal as long as it goes down in the first minute or two of operation.


Jim

 

[Buckeye Hydro]

Your pre-filter and carbon should be changed every 6 months -- at most. I personally change mine around 3-4 months, whenever the pressure starts to drop.

The DI resin should be changed/ordered whenever the TDS gets above 1.

The RO membrane is a bit (( though not all that much )) more complex. First you should know the rejection rate of your membrane (( mine happens to have a 96-98% rejection rate )), the tap water TDS, and finally the post RO (( but before the DI resin )) TDS.
Once the rejection rate is less then the stated rate, it is time to change the membrane -- should expect 2-3 years, with average TDS. ...

Todd is right on the money. Good post.

Russ

 

[Buckeye Hydro]

And yes - when the DI resin is exhausted, it will begin to release contaminants you used it to capture in the first place.

Russ

 

[Toddrtrex]

+.75 lol

I left out .25 because to me the DI reading shouls ALWAYS be ZERO. That is the point of the DI stage. I change mine WHEN I see 1 TDS.

This is what the filterguys say about it which matches what Spectrapure says as well.

I was about as clear as mud there --- I meant that I order my DI resin/change it (( try to have back up on hand at all times )) when I see the TDS go to 1.

 

[Palting]

what would you think is the cut off point of ppm of the ro /di water before replacing filters. my reading is up to 4ppm. chicago water here

Your pre-filter and carbon should be changed every 6 months -- at most. I personally change mine around 3-4 months, whenever the pressure starts to drop.

The DI resin should be changed/ordered whenever the TDS gets above 1.

The RO membrane is a bit (( though not all that much )) more complex. First you should know the rejection rate of your membrane (( mine happens to have a 96-98% rejection rate )), the tap water TDS, and finally the post RO (( but before the DI resin )) TDS.
Once the rejection rate is less then the stated rate, it is time to change the membrane -- should expect 2-3 years, with average TDS.

An example, if my TDS (( tap )) was 100, and the post RO was above 5, that would give me a rejection rate of 95%; at that point I would order a new membrane.

For me (( at least at my old place, haven't tested the new place yet, but it is still Lake Michigan water )) I have a starting TDS of 155. My RO membrane was 3 years old when I last replaced it, and the DI resin was about 9 months old; I wasn't schedule to replace it, but I wasn't aware that they were going to do work on the pipes, and it trashed my membrane/resin.

stevercleeze, how old is your RODI, and have you changed any of the filters at all?

It took me a while to figure out RODI maintenance, and at first blush what Todd is saying seemed too much. With time and more reading and experience, I now know what Todd is saying is right on the money. Best way to make sure your RODI is at peak performance is to have a pressure gauge to monitor the pressure and replace the prefilters when the pressure starts to go down, have a TDS meter after the membrane but before the DI to monitor your membrane, and a TDS meter after the DI to monitor the DI. These monitoring "gadgets" are relatively cheap and will pay for themselves over time, by making sure you don't throw away the filter before it's time as well as protect your tank from the consequences of poor quality RODI from stale filters.

 

[evsalty]

I was about as clear as mud there --- I meant that I order my DI resin/change it (( try to have back up on hand at all times )) when I see the TDS go to 1.

My first stage DI just showed 1 this week. I almost shut it off right then lol. Since my Silica Buster DI is still very new I let it go but I will not make any more water until I replace the mixed bed DI. Since I live about 1 mile from Spectrapure I do not worry about having my next filter on hand .

 

[solitude127]

Here's a thread I always refer to.
http://www.reefcentral.com/forums/showthread.php?t=1415770