Would you change my RODI set up? Early resin exhaustion question

[t5Nitro]

Have an rodi from the filter guys when they were in business. Added components to it since then. From source water to output the order is as follows:

Source water > 1 micron sediment filter > 1 micron carbon block filter > 1 micron carbon block filter > BRS chloramine monster > dual 75 gpd RO membranes > mixed DI resin > storage tank.

Storage tank is 65 gallons. Resin from brs is exhausted with about 1 fill of the tank. I run the rodi on a Smart Buddie Booster Pump as well. Prefilters changed about every 3 to 4 months. Membranes twice a year. And as mentioned, resin about every fill of the storage tank. Looking to stop changing resin so often if possible.

Initial tds flush from prefilters, chloramine monster and membranes is on the mid 300s. I let that drain for about 10 mins until its closer to 9-10, then start supplying the resin.

 

[KStatefan]

Have you checked CO2 level in your water? That can burn thru resin quickly.

I would look at a going to a triple resin system.

 

[Darren in Tacoma]

What is interesting to me is that I get 1-2 tds after my RO membrane.

 

[KStatefan]

What is interesting to me is that I get 1-2 tds after my RO membrane.

CO2 does not show up on tds

 

[Billldg]

Getting a 1-2 TDS reading after the Membrane and before the 5th stage canister in your case is not uncommon. How old is the membrane on your system? I have good water in Georgia, and I still upgraded my 5 stage to a 7 stage simply by adding 2 more Resin stages.

 

[Billldg]

Also, have you looked at your local water chemistry make up. You should be able to google it and see if it has just Chlorine, or Chloramines. It will also show the TDS make up of the local water supply.

 

[KStatefan]

1-2 tds is excellent after the membrane with starting at mid 300s.

 

[LeftyReefer]

Do you have a DI bypass valve? So you aren't directing all that high TDS water through your DI resin each time?

I don't see one between your RO membranes and the DI canister.... might want to add one.

 

[Darren in Tacoma]

CO2 does not show up on tds

He gets 9-10 tds after the membrane. I get 1-2. I wasn't commenting on Co2 levels as I know nothing about it.

 

[JMetaxas]

Sure sounds like high Co2 in your source water. I have the same from my well and could exhaust a DI cartridge in about 100 gallons.

I've gone to separate Cation/Anion resins, followed by a mixed bed. The Anion resin catches the Co2 and lasts more than 2X what a single mixed bed lasts.

 

[Mike konesky]

Upgrades that would help imo are, spectrapure 99% membranes, .2 micron sediment after the 1 micron, .5 micron carbon blocks, and triple di. Check for co2 as stated above, as it will destroy resin quick.

 

[Shirak]

How are you flushing the initial RO water which is high in tds before sending it to the DI?

 

[t5Nitro]

Thanks for all the responses, I'll try to answer them here.

Also, have you looked at your local water chemistry make up. You should be able to google it and see if it has just Chlorine, or Chloramines. It will also show the TDS make up of the local water supply.

Looked at 2020 water quality report from water co website. Chloramines are present, as well as nitrate. No mention of chlorines, CO2 or TDS.

Do you have a DI bypass valve? So you aren't directing all that high TDS water through your DI resin each time?

I don't see one between your RO membranes and the DI canister.... might want to add one.

I unplug the input to the resin and let it drain down the sink for 10-15 minutes.

Sure sounds like high Co2 in your source water. I have the same from my well and could exhaust a DI cartridge in about 100 gallons.

I've gone to separate Cation/Anion resins, followed by a mixed bed. The Anion resin catches the Co2 and lasts more than 2X what a single mixed bed lasts.

Upgrades that would help imo are, spectrapure 99% membranes, .2 micron sediment after the 1 micron, .5 micron carbon blocks, and triple di. Check for co2 as stated above, as it will destroy resin quick.

Sure sounds like mine. Water quality report mentions total organic carbon removal met goals but doesn't mention what that is. No mention of CO2 or inorganic carbon in the document. Certainly sounds like it, though. I'll add more resin cartridges cation > anion > mixed.

How are you flushing the initial RO water which is high in tds before sending it to the DI?

Disconnect the input to the resin, run it down the drain 10-15 minutes.

 

[Buckster]

Checked my system. From the pump the water runs through the 3 filters on the bottom to the two above them. From there the water then goes through the 3 resins and then into my RODI holding container. Make sure this is the order of your filtration! I followed the instructions and watched the BRS video. The order is essential, you may have more filters and less resin than I do.

 

[Shirak]

Let the RO run like you do to flush it and before you plug it back into the DI take a sample and check the pH. Also take a jar full to an airy (outside or by an open window) location and bubble air through for an hour or so and check the pH
If it is CO2 it’s an easy fix of just letting the RO go to a holding container and bubbling air through for a day and then pumping through the DI with a small pump.

 

[t5Nitro]

Checked my system. From the pump the water runs through the 3 filters on the bottom to the two above them. From there the water then goes through the 3 resins and then into my RODI holding container. Make sure this is the order of your filtration! I followed the instructions and watched the BRS video. The order is essential, you may have more filters and less resin than I do.

I have mine running prefilters x3 > chloramine monster > RO membrane 1 > RO membrane 2 > mixed DI resin

Let the RO run like you do to flush it and before you plug it back into the DI take a sample and check the pH. Also take a jar full to an airy (outside or by an open window) location and bubble air through for an hour or so and check the pH
If it is CO2 it’s an easy fix of just letting the RO go to a holding container and bubbling air through for a day and then pumping through the DI with a small pump.

I can try this. Can pick up a cheapo API pH kit just to use as a comparison.

 

[Shirak]

I have mine running prefilters x3 > chloramine monster > RO membrane 1 > RO membrane 2 > mixed DI resin

I can try this. Can pick up a cheapo API pH kit just to use as a comparison.

Yep little pH strip or something. Curious to see what you find.
You could also run a test using 5g bucket of RO that has been bubbled for a day and then pump it through a new cartridge of DI. 5gal of water and you shouldn't see much resin color change at all. Since you were only getting 65g per cartridge before, even 5gal would caused some visible color change on the resin before bubbling.

Although your TDS is a tad high so that will run through the resin more than normal but it still should be way more than 65gal. Might look into some 98% rejection membranes. With 300tds source water you should be able to hit 4-5ppm

 

[DanTheReefer]

Only other suggestions I have besides all of the co2 comments is making sure the DI is packed really really tight. I also had a plumbing mistake where my RO tubing was running into the salt bin - when the system turned off the salt water would mix throughout the tubing and scorch the DI overnight. Seems obvious but took me quite a few DI canisters to figure that out, oh brother.

 

[t5Nitro]

Yep little pH strip or something. Curious to see what you find.
You could also run a test using 5g bucket of RO that has been bubbled for a day and then pump it through a new cartridge of DI. 5gal of water and you shouldn't see much resin color change at all. Since you were only getting 65g per cartridge before, even 5gal would caused some visible color change on the resin before bubbling.

Although your TDS is a tad high so that will run through the resin more than normal but it still should be way more than 65gal. Might look into some 98% rejection membranes. With 300tds source water you should be able to hit 4-5ppm

Probably true. I used to think Brs color changing resin was just bad. Now I have another new pack of prefilters and single cartridge mixed resin package which started to turn amber color very early in the course of making 20 gallons or so.

Only other suggestions I have besides all of the co2 comments is making sure the DI is packed really really tight. I also had a plumbing mistake where my RO tubing was running into the salt bin - when the system turned off the salt water would mix throughout the tubing and scorch the DI overnight. Seems obvious but took me quite a few DI canisters to figure that out, oh brother.

Ouch, that would be a headache to be changing every night haha. I have a shutoff valve between the DI output and the storage tank that I close. I did have some rodi back siphon in the past, so I added that.