I need help with my RO/Di unit (Aquatic Life twist-in 4 stages RO/Di unit - 100 gpd)

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Idech

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I got a good deal on a used Aquatic Life Twist-in 4 stages (100 gpd). The guy bought it last december and told me he only made about 7 gallons per week and his tap water TDS was 107 ppm. I calculated he made about 125 gallons of good water. This unit has an average rejection rate of 1:3.5. He lives in a different city than me but in my city the chlorine level is no more than 1 ppm. At 1 ppm chlorine, this unit will make 650 gallons of good water. So I figured I had about 525 gallons left and I made about 15 gallons so far. My tap water TDS is about 90 ppm.

At first, I noticed the unit only makes about 70 gallons per day instead of 100 (it takes almost 2 hours to make 5 gallons). I didn’t think much of it because my water pressure might be too low; I don’t have any way to measure it.

Then, after only using it 4-5 times and making about 20 gallons, today I noticed the water that I was mixing with salt was taking longer than usual to become clear. I thought the little white residues in the water was undissolved salt so I mixed it a little more and then poured it in my mixed saltwater bin with another 5 gallons that I had previously mixed. My bad, I didn’t check the TDS before doing it (saltwater is new to me, I’m learning the hard way).

Then I made another 5 gallons of RO/Di water and I noticed the same thing : tiny little white residues floating in the water. This time it couldn’t be undissolved salt so I thought it might be particles from the unit. I measured the TDS and it was at 35 ppm. The last batch of good water was 0 ppm. So this is a brand new problem that just appeared today, after doing a 5 gallons bucket.


Here are my questions :

1) what is causing these white floating residues ?
2) which cartridges do I have to change ? (The deionization cartridge has not changed color it seems. It’s still a uniform dark brown)
3) do I keep the saltwater mix that I have in my bin, which consists of 50% water with 0 ppm TDs (I think, by looking at it, but I didn’t test it before) and 50% water with 35 ppm with the white residue floating around ? I guess not, but I worked hard to make it and I’m so frustrated...

If I have to change all cartridges, I’ll be paying more than the full price and I didn’t even get all the accessories that came with it. I already had to buy one part separately. Sigh.
 
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I was in the same situation about two weeks ago with the same filter. I'm also new so I can't really help but I can say I only got about 100 gallons of good water. It might have been fine if I changed the filter but I upgraded to the bulk reef supply rodi unit and am so happy I did.
 

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So you can measure the TDS of the RO with installing the flush cap on the DI position. This will let you know how well the RO membrane is working. The Twist In will have a typical rejection rate of up to 98% but normal is 97%. When you go to test, run the water out of the RO for around 3 minutes and then take the TDS measurement. You would be looking for around 2 - 3 TDS out of the membrane with a 90TDS water supply.

Is you water supply treated with Chlorine or Chloramines or is it well water? It appears you are in Canada and I have found many water supplies in Canada are treated with Chloramines. You want to double check as this would require an additional Chloramine specific filter to be added.

DI resin should be bluish, brown is the color when exhausted.

See the link below on making sure the RO is not siphoning back through the DI into the RO membrane too.

Proper Reverse Osmosis Unit Placement - YouTube
 
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Idech

Idech

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So you can measure the TDS of the RO with installing the flush cap on the DI position. This will let you know how well the RO membrane is working. The Twist In will have a typical rejection rate of up to 98% but normal is 97%. When you go to test, run the water out of the RO for around 3 minutes and then take the TDS measurement. You would be looking for around 2 - 3 TDS out of the membrane with a 90TDS water supply.

Is you water supply treated with Chlorine or Chloramines or is it well water? It appears you are in Canada and I have found many water supplies in Canada are treated with Chloramines. You want to double check as this would require an additional Chloramine specific filter to be added.

DI resin should be bluish, brown is the color when exhausted.

See the link below on making sure the RO is not siphoning back through the DI into the RO membrane too.

Proper Reverse Osmosis Unit Placement - YouTube

Hello and thank you so much for your help, I really appreciate it ! This is all new to me and it can be a little overwheming. You’re right, I’m from Canada.

City water : the city will call me me back after checking tests that were done at or near my address. There are no chloramines and the chlorine levels in my area are 0.22 ppm or 0.23 ppm.

Flushing : I have installed the flush cap in the Di position and took the TDS reading after 3 minutes and it was 3 ppm. I tested the tap water and it was 83 ppm.

Proper unit placement : I’ve also checked the video on proper unit placement. See pictures below, am I right to think I’m okay ?

Di resin : about the Di resin, it is definitely dark brown, so completely exhausted (see picture).

Next steps : I bought new sediment and carbon cartridges last night. I will also order a new Di resin cartridge. Since the Di resin is exhausted, should I also change both the sediment and carbon cartridges or can those two wait ?

If I wait, how do I know when it’s time to change them?

Can I run the unit without the Di Resin cartridge or is it better not to ?

Can you tell me if those specs I found below are meant for my specific unit ?

*****************
« The carbon cartridge is the most important cartridge to change frequently. The carbon cartridge can filter about 2,500 gallons of water before being replaced IF your chlorine level is 1 ppm (parts per million). With a

2 ppm you can filter 1,250 gallons of water before needing to change, with a 3 ppm you can filter 833 gallons, and so on. Any chlorine not absorbed by a spent carbon cartridge will break down your membrane, thus greatly shortening its life.

The 2,500 gallon threshold is TOTAL water that passes through the unit. The Twist-In RO Unit has an average rejection ratio of 1:3.5. That means for every 1 gallon of good water produced you will reject 3.5 gallons

for a total of 4.5 gallons of water passed through the unit. At 1 ppm of chlorine, you can make about 650 gallons of good water before changing the carbon cartridge, 2 ppm you can make about 325 gallons, 3 ppm you can make about 217 gallons, and so on.

When the sediment cartridge needs to be changed, the production of water will reduce. Even with reduced water production, the cartridge will not allow anything larger than one micron to pass through the chamber. On average the sediment cartridge should be changed at every other carbon change.

With proper filter changes, the membrane could last up to two years. The membrane’s water production rating is based on 77°F water at 65 PSI. Any deviation from this

will affect the water production. Reference the conversion table below. You will notice that the warmer the water, the better the production. It is not advised that you introduce water from your water heater to increase water temperature. The membrane cannot handle temps over 100°F.

The color changing mixed bed resin DI cartridge will absorb the remaining TDS not filtered by the membrane. When mixed bed resin is new, it is a blue green color. When it gets wet, it will change a dark blue color. When the medium is spent it will change to a light brownish tan color. »

**********

Thank you !

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AquaticLifeProducts

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Ok so the detail you have above looks to match the Twist in cartridges. If you want a copy of the manual I can email one if you would like. You can email [email protected].

So the RO membrane appears to be working as we would expect. The RO can be run without the DI but I'm curious how you are measuring the TDS? With a TDS pen? If you install the DI now with the RO out at 3 ppm are you still getting high TDS out of DI filtered water line? The DI is still pretty dark and the top only looks to be brownish. The water will trickle from the top down.

If using a TDS pen, if there was any contamination in the container it could have been the problem when taking the measurement. I have rarely seen TDS be higher out of the DI than the membrane. Unless there is a chance that saltwater can back siphon into the DI cartridge from a saltwater storage container. But the cartridge would change color from the bottom up.

Might be good to double check.

At this point if the DI is still showing high TDS out it would be the only cartridge to change. The sediment and the carbon appear to be ok and with the calculated water volumes you should be good.

Let us know will be glad to help.
 
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@AquaticLifeProducts thank you, I will send an email to get the manual.

I did what you suggested, ie put the Di resin back and take a TDS measure (yes, I’m using a pen) and this time it’s a perfect 0, like it was before this happened.

So the problem we have on our hands seems to be something else than the cartridges. It might be something I’m not doing right, but I don’t know what and hope you can tell me.

(See the better picture of the Di resin and tell me if I need to change it but I believe it’s ok. I do have trouble with certain colors but this looks brown to me, not blue, and amber at the top, where it’s exhausted).

Here is the chronology of what happened from the beginning.

1- When I first got the unit, I laid it flat on the washing machine and used it to test the TDS. It read 35 ppm. Then I let it run for a few minutes and tested it again. It was 0 ppm.

2- I then started using the unit and made about 15 gallons of good water. Everything was fine.

3- Then yesterday, the problem I’m talking about on this thread happened. I made a good batch at 0 ppm. Then a bad batch at 34 ppm and then another good batch at 0 ppm. The bad batch also had an abundance of white floating residues.

Sometime yesterday the unit banged against the faucet a bit.

So the question now is :

Why am I having random good batches and bad batches ?

Is it because I laid it flat the first time for a while before using it upright ?

Is it because I banged it yesterday ?

If the Di resin isn’t the problem, I’m really confused. Thank you for helping me, let’s hope we figure it out soon. :)

BC642932-5CD6-4C95-B6AF-F278FCEC8A13.jpeg
 

PeterB113

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I got a good deal on a used Aquatic Life Twist-in 4 stages (100 gpd). The guy bought it last december and told me he only made about 7 gallons per week and his tap water TDS was 107 ppm. I calculated he made about 125 gallons of good water. This unit has an average rejection rate of 1:3.5. He lives in a different city than me but in my city the chlorine level is no more than 1 ppm. At 1 ppm chlorine, this unit will make 650 gallons of good water. So I figured I had about 525 gallons left and I made about 15 gallons so far. My tap water TDS is about 90 ppm.

At first, I noticed the unit only makes about 70 gallons per day instead of 100 (it takes almost 2 hours to make 5 gallons). I didn’t think much of it because my water pressure might be too low; I don’t have any way to measure it.

Then, after only using it 4-5 times and making about 20 gallons, today I noticed the water that I was mixing with salt was taking longer than usual to become clear. I thought the little white residues in the water was undissolved salt so I mixed it a little more and then poured it in my mixed saltwater bin with another 5 gallons that I had previously mixed. My bad, I didn’t check the TDS before doing it (saltwater is new to me, I’m learning the hard way).

Then I made another 5 gallons of RO/Di water and I noticed the same thing : tiny little white residues floating in the water. This time it couldn’t be undissolved salt so I thought it might be particles from the unit. I measured the TDS and it was at 35 ppm. The last batch of good water was 0 ppm. So this is a brand new problem that just appeared today, after doing a 5 gallons bucket.


Here are my questions :

1) what is causing these white floating residues ?
2) which cartridges do I have to change ? (The deionization cartridge has not changed color it seems. It’s still a uniform dark brown)
3) do I keep the saltwater mix that I have in my bin, which consists of 50% water with 0 ppm TDs (I think, by looking at it, but I didn’t test it before) and 50% water with 35 ppm with the white residue floating around ? I guess not, but I worked hard to make it and I’m so frustrated...

If I have to change all cartridges, I’ll be paying more than the full price and I didn’t even get all the accessories that came with it. I already had to buy one part separately. Sigh.
I have the same one as you. I would only change carbon cartridge( if di ionization is still good. Only times i ever noticed white parcipitate was when i held my mixed saltwater for more than 36hrs. Also i wouldnt heat your water as you mix it and buy a cheap TDS meter on amazon just to make sure you tds is always at 0.
 

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AquaticLifeProducts

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Few additional questions.

Since you are collecting in a bucket is this bucket used for anything else? Or only RODI water collection?

If you see the white material do you also see if when water is collected directly into a glass container that is able to be seen through? Or only when collected in the bucket?

If your TDS is 0 I'm not sure what would be left in the water supply that would produce what you are describing. The sediment and the carbon will pull out anything down to 5 microns. The membrane down to 0.0001 micron and the DI should remove any element with a charge.

I'm not sure what would precipitate out of the RODI water with 0 TDS in a clean container.

As for the high TDS at startup you typically will see some TDS in the startup and want to divert that water until the unit starts to read 0. Then start to collect.

I know TDS pens are popular but due to contamination in containers, I do like using an inline TDS meter so that you are only reading the TDS of the water flowing through the lines, not TDS in a container that could have residual material that could read as TDS on a pen measuring in the container.
 
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Since you are collecting in a bucket is this bucket used for anything else? Or only RODI water collection?
The bucket is reserved for collecting RODI water. I bought it 2 months ago.

If you see the white material do you also see if when water is collected directly into a glass container that is able to be seen through? Or only when collected in the bucket?
I have checked it through a drinking glass and it had the same white material as in the bucket.

Yesterday I made 25 gallons of good water and I checked the water many many times and it was always 0 ppm, sometimes 1 ppm briefly.

It is very odd.

Do you agree my Di resin cartridge is only about 1/6th used ?

You mention : « If your TDS is 0 I'm not sure what would be left in the water supply that would produce what you are describing. »

But when there was white particles, the TDS was 35 ppm, not 0 ppm. It became 0 ppm after I did the flush test you asked me to do (removing the Di resin).

Could this have anything to do with TDS creep ? Meaning the Di resin sometimes doesn’t work properly, for unclear reasons ?
 

AquaticLifeProducts

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Ok, that is good to know on the bucket.

DI Looks barely used at this point. 1/6th looks about right.

The flush cartridge on the ID was only a test to verify the RO membrane rejection rate. It should not had any impact on the DI cartridge or filter head the the DI attaches too.

TDS creep is typically seen out of the membrane when it sits but the DI will remove it normally. I have seen in some cases where DI resin sits and can have a TDS released in the water at start up, but nothing ever with particles. I think the only way particles could be made is if something came out of solution. And I have no idea what that could have been.
 
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I have seen in some cases where DI resin sits and can have a TDS released in the water at start up, but nothing ever with particles. I think the only way particles could be made is if something came out of solution. And I have no idea what that could have been.

Ok, so I guess we’ll conclude this is very odd and hope it doesn’t happen again ! If it does, I’ll report back here.

Thank you very much for your help Dave. :)

Maybe one last question if you don’t mind, is there any way to do a TDS creep bypass on my unit and if so, how?

Or would it be an overkill in my particular situation, with 83 ppm TDS in my tap water and 0.02 ppm chlorine ?
 

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Glad to assist.

The easiest way would be to start the system with the flush cap on the DI and run the RO for 3 minute +/- or until the TDS drops to normal levels. 2 -3 with your water supply.

Turn the water supply off, install the DI and then start it right back up.

This would be the easiest without going with a lot of additional valves and T's on the system.

Let me know if anything shows up.
 

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