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View Full Version : what parts of RODI do you change when TDS starts creepin?


Daddyrawg
07/15/2018, 06:25 PM
So Ive had this 4 stage rodi system for 3 months now from BRS and i'm no longer getting 0 tds readings.. what part of the system needs replacing to get back to 0 tds readings?

Thanks all

GQuinn
07/15/2018, 06:31 PM
So Ive had this 4 stage rodi system for 3 months now from BRS and i'm no longer getting 0 tds readings.. what part of the system needs replacing to get back to 0 tds readings?

Thanks all

It sounds like you need to change the DI cartridge. This is the last cartridge on the unit.

stingythingy45
07/15/2018, 06:31 PM
What is the TDS now? I change the sediment,both carbon, and the di. Kit is not bad from BRS.

tomreefer
07/15/2018, 06:38 PM
I change all filters every 6 months; Clean housing with bleach.

cincyjim
07/16/2018, 04:05 AM
I change all the filters myself.

rvareef
07/16/2018, 05:03 AM
So Ive had this 4 stage rodi system for 3 months now from BRS and i'm no longer getting 0 tds readings.. what part of the system needs replacing to get back to 0 tds readings?

Thanks all

how hard is it creepin

MondoBongo
07/16/2018, 07:04 AM
when i see anything at or above 2ppm, i change the 3 main filters in the unit. carbon, sediment, and DI.

usually about once every 6 months or so, i change the RO membrane as well.

nereefpat
07/16/2018, 07:16 AM
If TDS is above zero, then the DI needs changed.

Since they are cheap, it's a good time to replace the other filters.

The RO membrane, however, should last a long time (years).

Daddyrawg
07/16/2018, 09:48 AM
when i see anything at or above 2ppm, i change the 3 main filters in the unit. carbon, sediment, and DI.

usually about once every 6 months or so, i change the RO membrane as well.

when you say 2 is that 002 PPM? o2r 200PPM.. ??

nereefpat
07/16/2018, 10:20 AM
when you say 2 is that 002 PPM? o2r 200PPM.. ??

2 ppm...or 002ppm...or 000002.000ppm

2ppm

MyMocha
07/16/2018, 10:36 AM
I always change the DI when my ro/di raises above 2 ppm.That's the one you change out the most. If that doesnt bring it to 0, I replace the others. I've only change the membrane 3 or 4 times in hmm..many many years... 15?

mcgyvr
07/16/2018, 10:53 AM
The filters that reduce TDS are the RO membrane and the DI cartridge..

The others (prefilters) are really about protecting the RO membrane and have very little if any effect on TDS..
As the prefilters get clogged/used the pressure drops and then RO membrane performance suffers..

As stated typically people replace their prefilters at the same time as the DI resins but there are times when the DI could be depleted faster than the prefilters are used up..

As I only make like 5-10G a week if that I replace my prefilters and DI every year and a half now.. I was making more before and changing them every year..
My incoming TDS is also only 60-70ppm and our water is pretty clean/sediment free,etc...

You can typically tell that the prefilters are exhausted by watching premembrane/post prefilter pressure (if you have a gauge there) or just simply knowing how fast you are making RO water and change it when your rejection rate gets greater than you want to accept..

MondoBongo
07/16/2018, 01:07 PM
when you say 2 is that 002 PPM? o2r 200PPM.. ??

when TDS (Total Dissolved Solids) measure AT or ABOVE 2PPM (Parts Per Million) as measured by my inline TDS meter, i change the filters.

leading 0's have no effect on the number. we're using integer types here, not strings.

lapin
07/16/2018, 01:24 PM
So Ive had this 4 stage rodi system for 3 months now from BRS and i'm no longer getting 0 tds readings.. what part of the system needs replacing to get back to 0 tds readings?
Thanks all

Sounds like you have a new RO/DI . Good choice. No more trips to the LFS. Wooo Hooooo
When your TDS is over 0, this means your DI resin can not rid you water of dissolved solids.
At this point I would change out the pre-filters and the DI resin. Pre filters on amazon or ebay are dirt cheap. The charcoal one cost a bit more and you might not have to change it as often depending on whats in your water. I change mine about every 5th time.
Make a note as to when this was. Keep a log of when you do this. When you notice that you are changing the pre-filters and DI a lot sooner than normal its time to look at changing your RO cartridge.

ROB2005
07/19/2018, 05:58 AM
Also, a small note, make sure you get carbon filters that not only filter chlorine, but chloramines as well. Before I made the change, the unfiltered chloramines caused my di resin to be consumed faster than normal

PatW
07/19/2018, 06:32 AM
I agree with the others. It is probably your DI cartridge that is depleted. It almost certainly is not the RO filter. I have had a BRS RO filter for over three years and it is still fine and I make quite a bit of RODI water.

I would suggest that you get the BRS color changing resin when you repack the cartridge. The resin changes from blue to tan as it is depleted. It costs a bit more but I like it.

mcgyvr
07/19/2018, 08:05 AM
Also, a small note, make sure you get carbon filters that not only filter chlorine, but chloramines as well. Before I made the change, the unfiltered chloramines caused my di resin to be consumed faster than normal
Assuming your city uses chloramines of course..
Not all do..

Conchman
07/19/2018, 09:24 AM
Ditto, resin. When my TDS moves off of 0, I change. Rest I change every 6, one only annually.

reeefninja
07/22/2018, 11:05 PM
Most probably do resin

laverda
07/23/2018, 01:23 AM
It sounds like a lot of people are spending a lot of money replacing filter cartridges way more often than needed. When the tds increases it in no way indicates your first two stages need to be replaced in most cases. Unless your making a lot of water you DI should last longer than 3 months. There are many thing that affect the TDS coming out of your membrane and there for how fast your DI resin is depleted. Some of those things are, source water TDS, water tempature, water pressure, rejection ratio of your membrane, if you flush your membrane and for how long, if you produce water in small batches at a time and CO2 levels in your water.
I used to get years out of my resin. Recently I started going through them very quickly even though I make substantially less water now. My best guess is the city change to primarily ground water as my CO2 levels are what is using my DI resin up. I verified this by taking a water sample from before my DI cartridge and measuring the PH and got 7.12. Than I airatted the sample and the PH tested at 8.6.
You need to at least test you water before it enters you DI cartridge to get an idea what the problem might be. I have a fairly complex RO/DI with 2 prefilters, 2 carbon blocks, 2 membraines, a booster pump and 2 DI cartridges. So the cost of replacing the prefilter and carbon blocks adds up especially if they are not the problem as in the case of excess CO2.