Rodi new system not zero TDS output

josvanmeer · Jul 9, 2020

Hey everyone,

Even though my LFS has 0 tds water I got tired of picking water up every time a water change was due or I needed to top off my ATO container. So I bought this aquatic life buddy ro system from amazon, 4 stage 50gpd system because I only have a 40g tank and that’s more than enough. But I just made some water with it and the first 10 gallons it made (after flushing it properly of course) I am still measure the tds between 10-17. Is this because it’s new or is something wrong?

WIReefer · Jul 9, 2020

josvanmeer said:
Hey everyone,

Even though my LFS has 0 tds water I got tired of picking water up every time a water change was due or I needed to top off my ATO container. So I bought this aquatic life buddy ro system from amazon, 4 stage 50gpd system because I only have a 40g tank and that’s more than enough. But I just made some water with it and the first 10 gallons it made (after flushing it properly of course) I am still measure the tds between 10-17. Is this because it’s new or is something wrong?

Could be just some rough water at your home, do you have well or city water?

wphan · Jul 9, 2020

Is it just RO? Do you have a DI portion? I know aquatic life sells two different models.

Reef. · Jul 9, 2020

When did you test the water?

I normally keep testing till the water is 0 then collect, I need to keep rinsing the cup I use to test as that can throw off the reading, even in when the water is 0 the container can give a reading higher.

josvanmeer · Jul 9, 2020

WIReefer said:
Could be just some rough water at your home, do you have well or city water?

City water, tap water is about 350 tds

josvanmeer · Jul 9, 2020

wphan said:
Is it just RO? Do you have a DI portion? I know aquatic life sells two different models.

I have the 4 stage which includes the DI resin module as well

josvanmeer · Jul 9, 2020

Reef. said:
When did you test the water?

I normally keep testing till the water is 0 then collect, I need to keep rinsing the cup I use to test as that can throw off the reading, even in when the water is 0 the container can give a reading higher.

I collected two separate jugs of 5 gallons each, first jug was 17 tds the second was 10 tds, directly in the jug with the tds meter

BlueZreef · Jul 9, 2020

350...yikes. Keep in mind, membranes typically have a rejection percentage, so let’s say you have about a 97% rejection, that still leaves 10.5 TDS coming out after the membrane. The RO buddy units are pretty basic for the TDS load you have. Where I’m at I get 60 out of the tap so I expect 1-2 TDS out of the membrane (sometimes it will go to 0 but probably has some amount). DI takes care of the rest. Ideally you should look at what is in your water and buy a unit ideal to your water. Info should be online from your water provider (they mail out reports as well).

Reef. · Jul 9, 2020

josvanmeer said:
I collected two separate jugs of 5 gallons each, first jug was 17 tds the second was 10 tds, directly in the jug with the tds meter

that’s my point, you don’t know if the TDS is from the jug or the water, if the TDS is not 0 I wouldn’t be making 10g of water. I would look to see where the TDS is coming from, as I am guessing you won’t want to use that water.

AcroNem · Jul 9, 2020

I think there's some stuff in your containers, it wouldn't take much to contaminate it. Try measuring in a glass that you've rinsed with DI water several times

Auquanut · Jul 9, 2020

Probably from your container. Consider purchasing an inline TDS meter. It's much more convenient and a breeze to install. Should also give a much more accurate reading. I use this one, and it has worked well for a few years now. https://aquarium.bulkreefsupply.com...FxSzXMd7YwH-&method=and&isort=score&view=grid

proxy001 · Jul 9, 2020

I ve been through that and made the mistake of ignoring it for years. TDS should read zero or close to zero (1, 2) if not you have a setup problem. Make sure your DI resin is packed with no water pocket.

josvanmeer · Jul 9, 2020

Auquanut said:
Probably from your container. Consider purchasing an inline TDS meter. It's much more convenient and a breeze to install. Should also give a much more accurate reading. I use this one, and it has worked well for a few years now. https://aquarium.bulkreefsupply.com/search?p=R&srid=S1-1DFWP&lbc=bulkreefsupply&w=inline tds meter&url=https://www.bulkreefsupply.com/triple-inline-tds-meter-trm-1-hm-digital.html&lgsku=200219&rk=7&uid=211315506&sid=1&ts=custom&SLIPid=1594325763025&rsc=SewJFxSzXMd7YwH-&method=and&isort=score&view=grid

Thanks I will look into that. I just moved recently and the jugs probably did collect debris.

josvanmeer · Jul 9, 2020

AcroNem said:
I think there's some stuff in your containers, it wouldn't take much to contaminate it. Try measuring in a glass that you've rinsed with DI water several times

I will do that when I get home. I did actually measure one glass with the same water in it and it read zero so it tonight I will rinse those jugs out and start over while they are rinsed out and then I am guessing they should end up with 0 tds water

piranhaman00 · Jul 9, 2020

Even a drop of saltwater will contaminate (create conductivity ie TDS) in many gallons of water.

And FWIW, the RO Buddie worked great for me while I used it. Great little unit.

AcroNem · Jul 9, 2020

With that slow of a flow rate you could put pretty high TDS water through DI resin and it would still come out 0ppm it would just destroy your resin, so I'm guessing it's 0 unless you have low pressure and getting a terrible rejection rate.

josvanmeer · Jul 9, 2020

BlueZreef said:
350...yikes. Keep in mind, membranes typically have a rejection percentage, so let’s say you have about a 97% rejection, that still leaves 10.5 TDS coming out after the membrane. The RO buddy units are pretty basic for the TDS load you have. Where I’m at I get 60 out of the tap so I expect 1-2 TDS out of the membrane (sometimes it will go to 0 but probably has some amount). DI takes care of the rest. Ideally you should look at what is in your water and buy a unit ideal to your water. Info should be online from your water provider (they mail out reports as well).

Yeah they pull water from a lake here and it’s real muddy. They have improved over the years but tap water is not good. I am sure the resin should absorb everything that is rejected though, that’s how it works so nonetheless I should still end up with zero tds water I’m just in a location where i will end up changing my resin filter way faster than anyone else I think

josvanmeer · Jul 9, 2020

I will check again tonight with clean rinsed out jugs, since a clean cup of water tested at zero tds. I will follow up with new results later

Zenchi · Jul 9, 2020

There's an additional piece you can have for your RO/DI unit that should measure your TDS output. My tap TDS is 650 and my RO/DI outputs at 0. When the DI resin changes color fully, it may pop up to 3 and then I replace the resin.

I also run a second DI section as a safety net. You mentioned yours was a 4 part. Which 4 sections do you have on the unit?