RODI is not 0

[Salahunreal]

Hi good folks,
I'm in the process of setting up my first saltwater aquarium and working on couple of stuff for the preprations.
One of the things that wanted to have some help with is that my RODI water is around 6-7ppm after the DI while it is around 80 before the RODI unit.

From what i read so far that the reading after DI usually should be 0 almost and i ma not sure why i'm not reaching to low value like 0 or 1
my RODI bought it from the links below
Appreciate your inputs.


https://www.waterfilterman.co.uk/fish-keeping-water-filters/248-reverse-osmosis-water-filter-for-aquarium-discus-fish-marine.html

https://www.waterfilterman.co.uk/fish-keeping-water-filters/388-in-line-de-ionized-resin-di-water-filter-for-aquarium-reverse-osmosis-systems-5060282126923.html

TDS meter
https://www.waterfilterman.co.uk/water-testing-meters/212-hm-digital-dm-1-dual-in-line-tds-meter-reverse-osmosis-water-tester-0885156810310.html

 

[mcgyvr]

You bought a dirt cheap potentially inferior water filter system.. so thats always a possibility of why its output sucks..
BUT
Have you let the system run for a while if you just hooked it up? They will produce non-zero TDS for a bit when new and just after being started up..

Are you sure you are measuring the TDS at the output of the DI stage and not just after the RO membrane?

And are you measuring it immediately after being produced in a clean glass/container?

 

[joesig]

Doesnt look like you have any pre filters most run pre filter carbon carbon or 2pre 2 carbon then ro the di or 2di
The only tips i can give you is bypass the di resin untill the tds in reaches the lowest number then run it through the di and flush the membrane before you run it through your di


Sent from my iPhone using Tapatalk

 

[Scrubber_steve]

Hi good folks,
I'm in the process of setting up my first saltwater aquarium and working on couple of stuff for the preprations.
One of the things that wanted to have some help with is that my RODI water is around 6-7ppm after the DI while it is around 80 before the RODI unit.

From what i read so far that the reading after DI usually should be 0 almost and i ma not sure why i'm not reaching to low value like 0 or 1
my RODI bought it from the links below
Appreciate your inputs.


https://www.waterfilterman.co.uk/fish-keeping-water-filters/248-reverse-osmosis-water-filter-for-aquarium-discus-fish-marine.html

https://www.waterfilterman.co.uk/fish-keeping-water-filters/388-in-line-de-ionized-resin-di-water-filter-for-aquarium-reverse-osmosis-systems-5060282126923.html

TDS meter
https://www.waterfilterman.co.uk/water-testing-meters/212-hm-digital-dm-1-dual-in-line-tds-meter-reverse-osmosis-water-tester-0885156810310.html

It should read about 4ppm after it passes through the RO filter, & at 80ppm from tap, definately should read zero after going through the DI.
Make sure you don't have the flush water line connected to the DI filter rather than the RO line.

 

[heathlindner25]

Looks really out dated.

 

[Scrubber_steve]

The unit looks fine to me.

Pre - Filter 1: 5 Micron Sediment Water Filter

Pre - Filter 2: Carbon Water Filter

50 GPD Reverse Osmosis Membrane
High quality membrane Made in the USA

Finishing with a DI resin filter.

He's obviously on a decent town water supply with TDS of only 80ppm.

I would fit a pressure guage not only to make sure your pressure feeding the unit is high enough, but a decrease in pressure shows your pre-filters are blocking up.

If you've hooked it up correctly, and the water pressures good, perhaps the TDS meter is wonky

 

[Salahunreal]

My 10 days old son is sleeping on my chest and as long I put him to bed, he wide open his eyes and "mouth". I think he's addicted to the heart beats .
I'm reading your inputs and really appreciate it. It's 3 am in Stockholm so I'll get back with detailed replies later on.
Thanks all.

Sent from my ONE A2003 using Tapatalk

 

[Dmorty217]

My 10 days old son is sleeping on my chest and as long I put him to bed, he wide open his eyes and "mouth". I think he's addicted to the heart beats .
I'm reading your inputs and really appreciate it. It's 3 am in Stockholm so I'll get back with detailed replies later on.
Thanks all.

Sent from my ONE A2003 using Tapatalk

Congrats on your newborn! Cherish every moment they grow up quick!

 

[mcgyvr]

Make sure you have packed the DI chamber very well..
Those crappy horizontal ones are known for causing issues as the water finds a channel through and isn't treated well as its just missing making contact with the resin..

If you can mount it vertically it can help.. But I personally would change it out with a proper vertical DI stage.... The rest of the system is "ok" but changing that DI stage for the better vertical type is worth the money IMO...

 

[outy]

The unit looks fine to me.

Agreed but it surely has way to small of a pre filter and one would need to change out the carbon rapidly compared to standard sized units.

I'm guessing a cheap membrane is being used so we have a few more TDS leaving the membrane then should be.

Yes pressure gauges are cheap and you don't want to under drive the membrane.

For future reference I would get a 75gpd 98% membrane, and upgrade to 2 normal sized filter housings for at least 2 carbon blocks. If the water going in is semi clean the smaller pre filter might make it. Ive been using those smaller Di canisters for decades with no trouble, but I have really clean water.

 

[Scott07]

I have what looks to be the same RODI system as the OP. It's branded differently, but looks exactly the same. I'm not saying its a great filter by any means, but... it's met my expectations and I've never found a need to replace it in my short time in the hobby. I think I've replaced or upgraded every other piece of equipment i own at least 3 times over, but so far haven't found a need to replace this unit. I replace the pre-filters every 4 or 5 months to be safe, and i get the standard year and a half or two years out of a 50gpd membrane. TDS coming out of the membrane is always between 4 and 6. I use the DI cartridge linked as well. It is a vertical unit if its indeed the same as mine. It comes with clips to secure it vertically to the RO housing. Water out from my DI is always zero unless the resin needs changed.

This unit should be capable of producing zero tds water without a problem if set up correctly. My advice would be to double check the flow through the unit, make sure everything is hooked up correctly.... and then from there it has to be an issue with either the pre-filters, the RO membrane, or the DI resin.... something needs changed out.

 

[slief]

It should read about 4ppm after it passes through the RO filter, & at 80ppm from tap, definately should read zero after going through the DI.
Make sure you don't have the flush water line connected to the DI filter rather than the RO line.

4 ppm after going through the RO? That's pretty high for 80 ppm water unless he has really low pressure or a really poor quality membrane. I get 2ppm with 300+ TDS tap from my Spectrapure unit. Heck, even on a bad day when I have 475 TDS tap, I get 3 TDS out of my RO membrane. At 4ppm, I know it's time to replace my RO membrane. That said, I wish our tap water was 80 TDS!

 

[NS Mike D]

While not knowing how much water you need tp produce each week, the unit looks fine. In the reviews, someone has 250ppm tap water and getting 0 -2 TDS final product.

The reviews say they have very good customer service, I suggest contacting them. You have sufficient pre-filters and while 50GPD may take a while to collect what you need, the new unit should work fine with 80ppm tap.

+1 on letting it run a bit before collecting water and making sure you are testing the correct output.

I took use a portable cheap RO/DI unit that looks similar. The pre filers are rated for 1500 gallons. I make 10 gallon per week when I am not being lazy. I just changed the pre filters and DI after 2 1/2 years. The RO is rated for another 6 months. I'd prefer a better/bigger unit, but that isn't in the cards for me so the one I have works. Fish and corals are happy

 

[Scrubber_steve]

4 ppm after going through the RO? That's pretty high for 80 ppm water unless he has really low pressure or a really poor quality membrane. I get 2ppm with 300+ TDS tap from my Spectrapure unit. Heck, even on a bad day when I have 475 TDS tap, I get 3 TDS out of my RO membrane. At 4ppm, I know it's time to replace my RO membrane. That said, I wish our tap water was 80 TDS!

A typical thin filmed membrane will normally reject 90% or more of the dissolved solids. 95% is quite good, & the rejection will be 100% after going through the DI filter.

 

[Scrubber_steve]

Make sure you have packed the DI chamber very well..
Those crappy horizontal ones are known for causing issues as the water finds a channel through and isn't treated well as its just missing making contact with the resin..

If you can mount it vertically it can help.. But I personally would change it out with a proper vertical DI stage.... The rest of the system is "ok" but changing that DI stage for the better vertical type is worth the money IMO...

I use a DI cartridge that looks the same as the OP's. I mount it vertically and have the input side on the bottom so the water has to move upwards. This eliminates channeling.

 

[Salahunreal]

Well, yeah it is quite cheap but my limitation is the size. I am living in an apartments so i am tight on space.
1- Yes I let the system run for like 12 hours and i keep use for tea and coffee or cleaning the windows/ plants
2- Yes, the meter is connected to the DI output directly
3-Yes, I let it run for about 10 minutes to produce one liter usually and flush it sometimes.

 

[NS Mike D]

i would contact the manufacturer and let them know your test results. you may have a unit that got passed quality control.

 

[Salahunreal]

Doesnt look like you have any pre filters most run pre filter carbon carbon or 2pre 2 carbon then ro the di or 2di
The only tips i can give you is bypass the di resin until the tds in reaches the lowest number then run it through the di and flush the membrane before you run it through your di

Sent from my iPhone using Tapatalk

I already let the water run with RO first for a while and then connected the DI but I think i know the reason now why

The unit looks fine to me.

Pre - Filter 1: 5 Micron Sediment Water Filter

Pre - Filter 2: Carbon Water Filter

50 GPD Reverse Osmosis Membrane
High quality membrane Made in the USA

Finishing with a DI resin filter.

He's obviously on a decent town water supply with TDS of only 80ppm.

I would fit a pressure guage not only to make sure your pressure feeding the unit is high enough, but a decrease in pressure shows your pre-filters are blocking up.

If you've hooked it up correctly, and the water pressures good, perhaps the TDS meter is wonky

I have the pressure guage but missing the connections. Placed an order and will see what pressure I have. What would be the normal or good pressure?

Make sure you have packed the DI chamber very well..
Those crappy horizontal ones are known for causing issues as the water finds a channel through and isn't treated well as its just missing making contact with the resin..

If you can mount it vertically it can help.. But I personally would change it out with a proper vertical DI stage.... The rest of the system is "ok" but changing that DI stage for the better vertical type is worth the money IMO...

You know what, you are right in two points. The resin is not packed to the top. I put it vertically and I can see the resin is not full.
Plus my TDS reading started reaching 3 after testing it in vertical for an hour or so. I will see how to fix it vertically perminiatyly. I am very tight on space. I installed an Ikea shelf under the sink and it barely fit there. I might plan moving it to another spot in the flat but will see.

Agreed but it surely has way to small of a pre filter and one would need to change out the carbon rapidly compared to standard sized units.

I'm guessing a cheap membrane is being used so we have a few more TDS leaving the membrane then should be.

Yes pressure gauges are cheap and you don't want to under drive the membrane.

For future reference I would get a 75gpd 98% membrane, and upgrade to 2 normal sized filter housings for at least 2 carbon blocks. If the water going in is semi clean the smaller pre filter might make it. Ive been using those smaller Di canisters for decades with no trouble, but I have really clean water.

If i moved the unit then I will have more space but we will see about that. Thanks for the input.

I have what looks to be the same RODI system as the OP. It's branded differently, but looks exactly the same. I'm not saying its a great filter by any means, but... it's met my expectations and I've never found a need to replace it in my short time in the hobby. I think I've replaced or upgraded every other piece of equipment i own at least 3 times over, but so far haven't found a need to replace this unit. I replace the pre-filters every 4 or 5 months to be safe, and i get the standard year and a half or two years out of a 50gpd membrane. TDS coming out of the membrane is always between 4 and 6. I use the DI cartridge linked as well. It is a vertical unit if its indeed the same as mine. It comes with clips to secure it vertically to the RO housing. Water out from my DI is always zero unless the resin needs changed.

This unit should be capable of producing zero tds water without a problem if set up correctly. My advice would be to double check the flow through the unit, make sure everything is hooked up correctly.... and then from there it has to be an issue with either the pre-filters, the RO membrane, or the DI resin.... something needs changed out.

I think i should add more DI resin and put it vertically. I got 3 TDS when let it on vertical pos for an hour.

While not knowing how much water you need tp produce each week, the unit looks fine. In the reviews, someone has 250ppm tap water and getting 0 -2 TDS final product.

The reviews say they have very good customer service, I suggest contacting them. You have sufficient pre-filters and while 50GPD may take a while to collect what you need, the new unit should work fine with 80ppm tap.

+1 on letting it run a bit before collecting water and making sure you are testing the correct output.

I took use a portable cheap RO/DI unit that looks similar. The pre filers are rated for 1500 gallons. I make 10 gallon per week when I am not being lazy. I just changed the pre filters and DI after 2 1/2 years. The RO is rated for another 6 months. I'd prefer a better/bigger unit, but that isn't in the cards for me so the one I have works. Fish and corals are happy

That's what i thought also. the reviews were good and the system really looks like other pico RODI system. I bought it due to space limitation but will Now i reached 3 TDS after putting the DI vertically

A typical thin filmed membrane will normally reject 90% or more of the dissolved solids. 95% is quite good, & the rejection will be 100% after going through the DI filter.

I use a DI cartridge that looks the same as the OP's. I mount it vertically and have the input side on the bottom so the water has to move upwards. This eliminates channeling.

This is good idea i think to have it upside down. Yeah.. putting it vertically looks like making the difference here as I got 3 after I tried it.

 

[slief]

A typical thin filmed membrane will normally reject 90% or more of the dissolved solids. 95% is quite good, & the rejection will be 100% after going through the DI filter.

Not sure what I was thinking. That does work out to be about 95% which is quite good. I use Spectrapure 99% rejection membranes but even their 90% membranes reject better than 90% so I am used to much lower TDS out of my RO membrane despite having much higher TDS. If I had 4 TDS with 80 TDS tap, something would be wrong in my case but that is because of the membranes I use.

That said, as would be expected from any properly functioning RODI, I always have 0 TDS out of the first stage DI. I get a thousand or so gallons out of the first DI stage. I swap that stage as soon as I see 1 TDS to preserve my 2nd stage DI which then lasts me thousands of gallons.

 

[Salahunreal]

Congrats on your newborn! Cherish every moment they grow up quick!

yeah tell me about it, still staring at my oldest 3 years son and looking at the newborn one and seeing how time is running fast. Still remember all the details of the 1st one like it happened yesterday.
:headwallblue: