Please assist! New RO unit

[Bones29]

Evening all, new here so please be gentle! I’m pretty much ready to take a hammer to my new RO unit as it does not matter what I do the output TDS stays at 13. It’s new, all filters are new, membrane & DI resin is new. Today I wanted to make some water for the first time. I put the unit together a couple of weeks ago, flushed through and all was good. I’ve used the unit with over 100 litres of water today and it’s just all been wasted as it won’t read lower than 13. I’ve just about had enough of it now.
Unit is a 6 stage, water pressure is boosted with a pump to around 85psi, water coming in is 300, I just can’t work out how to get the outlet water TDS down to 0. What am I doing wrong??

 

[TX_REEF]

Can you share the details of the unit (brand, link to it) as well as a short video of the unit? The only way I can imagine that happening is if modules are somehow being skipped.

 

[Bones29]

So it’s a 50GPD Streamline 6 stage unit, running around 80psi pumped pressure. Producing water both in waste & RO. Ive now removed the DI resin & final filter to test the membrane so the RO is now coming directly out of the membrane instead of through DI resin & the final stage. It’s still reading 13 on the TDS ‍ Im going to leave it to flow through for a while and see if it comes down. I’ve bought another membrane just in case this is the problem but as with anything I seem to buy, nothing ever works first time! I’ve wasted so much water it’s criminal! ‍

 

[Tcook]

What is tds immediately after the RO membrane?

/sorry. You posted that. The unit looks like a 4 stage. Is there something not pictured? Do you have high chloramines in your city water that could exhaust your resin?

 

[Bones29]

It’s a 6 stage but I have removed the last 2 stages including the DI resin to test the membrane. This is a new unit, never produced RO as this is my first use & the TDS is reading 13 so can’t use in the tank. So the DI resin is new, the RO water has never shown less than 13 so can’t be exhausted. Water in is 320 TDS. TDS meter is brand new. I just can’t work out why it won’t drop & I’m getting really frustrated with the setup.

 

[Gtinnel]

So before the membrane the water feeding it is 320tds and the water coming out of the membrane is 13? If so that means your membrane has a 96% rejection rate which seems reasonable to me.
Was the tds after the DI resin also 13? If so either your resin is depleted or the water isn’t flowing through it properly. If the resin isn’t compacted well then water can form channels through the resin and it won’t work properly. From your pictures it also looks like the resin canister may have been laying down horizontally, which is not an ideal setup.

 

[Bones29]

So before the membrane the water feeding it is 320tds and the water coming out of the membrane is 13? If so that means your membrane has a 96% rejection rate which seems reasonable to me.
Was the tds after the DI resin also 13? If so either your resin is depleted or the water isn’t flowing through it properly. If the resin isn’t compacted well then water can form channels through the resin and it won’t work properly. From your pictures it also looks like the resin canister may have been laying down horizontally, which is not an ideal setup.

So at present the DI resin is not attached in the photo, when the resin was attached it still read 13. I’ve read a lot about the resin and packing it tight, I’ve packed it as tight as possible where I cannot get anymore into the chamber, it’s tapped down and the chamber looks full. Surely putting the DI resin into the unit this should reduce the TDS? I surely can’t use RO water with a TDS reading of 13?

 

[exnisstech]

13 before di and 13 after means the di is depleted, garbage, or being bypassed IMO

 

[Tcook]

Or the sensor inline after the membrane is junk. These tds meters are not very hi tech or expensive. Might want to replace that sensor or consider a 3 way so you can go before and after the resin.

 

[Gtinnel]

I hate to ask such an obvious question, but when your di resin was installed the sensor was after the di resin right? If so you would’ve had to move it when you removed the di resin?

Also is your resin color changing, if so has it changed colors, or can you see an obvious area that has been depleted?

Do you happen to use well water? I’ve never been on well water but my understanding is that it can very quickly deplete di resin.

 

[Justdrew]

The post from last week with the same symptoms had the DI cartridges installed upside down.

 

[Gtinnel]

The post from last week with the same symptoms had the DI cartridges installed upside down.

I would’ve never even considered that.

 

[Bones29]

The post from last week with the same symptoms had the DI cartridges installed upside down.

Not sure how I could have it the wrong way round as it’s got a big arrow on it for direction flow

 

[Bones29]

I would’ve never even considered that.

I

I hate to ask such an obvious question, but when your di resin was installed the sensor was after the di resin right? If so you would’ve had to move it when you removed the di resin?

Also is your resin color changing, if so has it changed colors, or can you see an obvious area that has been depleted?

Do you happen to use well water? I’ve never been on well water but my understanding is that it can very quickly deplete di resin.

That’s correct, I’ve unplugged the fittings to remove the DI resin so now the fitting is fitted directly after the membrane. Resin is brand new, same colour with no change in the colour. Water is mains water

 

[KStatefan]

Not sure how I could have it the wrong way round as it’s got a big arrow on it for direction flow

Can you share a picture of the DI section?

 

[Bones29]

I would’ve never even considered that.

How can having it the wrong way round cause the filter to fail? The resin sits in a tube with a fitting at each end so it confuses me how this would fail? Each fitting in the ends is the same

 

[KStatefan]

How can having it the wrong way round cause the filter to fail? The resin sits in a tube with a fitting at each end so it confuses me how this would fail? Each fitting in the ends is the same

It has come up multiple times over the years here.

 

[Gtinnel]

How can having it the wrong way round cause the filter to fail? The resin sits in a tube with a fitting at each end so it confuses me how this would fail? Each fitting in the ends is the same

Most traditional di filters (used for aquariums at least) are not uniform. They have a gasket on one side that prevent the water from flowing back out before it flows through the resin

 

[Bones29]

Most traditional di filters (used for aquariums at least) are not uniform. They have a gasket on one side that prevent the water from flowing back out before it flows through the resin

I will need to check this in case the ends have been put on the wrong ends when I bought it, thankyou

 

[Bones29]

Can you share a picture of the DI section?

So here is the unit with all the filters attached and showing the arrows of flow.
Any advice on packing the resin into the chamber? Do I tamp it down and make sure I can’t get a single grain more inside? I really feel like I can’t get any more inside the chamber.