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View Full Version : RODI not doing what it's supposed to!


neoh
05-19-2013, 08:07 AM
I got a ro/di 4 stage off a member here, with a tds meter. I hooked everything up (completely blind - never done this before) and everything seems to be fine - except the fact that my out tds is showing 350ppm.

So, I figured I had the waste water/good water lines reversed - changed them around, and I still have the same TDS readings.

Every line I change around, my tds readings are still high.

Am I missing something here? It's not rocket science.

http://img716.imageshack.us/img716/9137/rodi.jpg

RumRunner
05-19-2013, 08:24 AM
In mine waste water and good water is opposite the pic

RumRunner
05-19-2013, 08:40 AM
or not wtf do I know

scherzo
05-19-2013, 08:51 AM
Is that last filter on the bottom right a DI filter? If so, it should be last.

The water flow should be

1) sediment
2) carbon
3) RO membrane
4) DI

Here is a video explaining it.

http://youtu.be/Y0OeFInDFMk

scherzo
05-19-2013, 08:53 AM
Also if your unit has a back flush- you should do it for 30 mins or so.

300 TDS is really high. If you're in the lower mainland you should be at 8-20 TDS right out of the tap.

neoh
05-19-2013, 09:44 AM
scherzo: it doesn't appear to have a backflush, I was looking to do this earlier. I've been running the unit for about 6-8 hours now filling up buckets, so it has had plenty of time to rinse out.

I also don't know if the bottom right is a DI filter. Though I should probably take it all apart and check! The way the system is put together, it doesn't seem as though the unit is put together the way that is described in the video.

SeaHorse_Fanatic
05-19-2013, 11:01 AM
How old or new are the filter media?

11purewater
05-19-2013, 01:28 PM
Know any body with another TDS meter too verify your readings

11purewater
05-19-2013, 01:38 PM
Is that last filter on the bottom right a DI filter? If so, it should be last.

The water flow should be

1) sediment
2) carbon
3) RO membrane
4) DI

Here is a video explaining it.

http://youtu.be/Y0OeFInDFMk

+1 looks like you're running DI into the membrane(still doesn't explain 300 tds)

Evilweevil
05-19-2013, 02:40 PM
I had this exact problem with mine and after some tinkering I bought a brand new vertex rodi unit fixed the problem

scherzo
05-19-2013, 03:24 PM
Running it doesn't actually clear out the RO membrane. It actually clogs it up.

You can flush it by temporarily removing the restrictor on the waste line. Do you have a pic of that?

mike31154
05-19-2013, 03:35 PM
Though I should probably take it all apart and check! The way the system is put together, it doesn't seem as though the unit is put together the way that is described in the video.

That's a great idea, particularly if you have little to no information as to filter media condition from the previous owner. It could well have been sitting for some time, either dry or wet & has all kinds of nasty stuff bound in the sediment and/or carbon stages. The membrane could also be shot if it has dried out.

I know on my system, the center fitting out of the membrane is the pure water & the waste is the outer fitting & that's usually the way most membrane housings work, but one never knows for sure without confirmation of the manufacturer or by opening it up. The way most membranes are built, the water is pushed from the outside to the inside while flush water rinses the outside of the membrane. So it makes sense that the center fitting on the membrane is the pure water.

Also make sure there is a restrictor on the waste line somewhere. Some are built into the waste line fitting, some are obvious combination valve/restrictor units that you can use to either flush the membrane or produce pure water by closing the valve. With the restrictor in line & working properly, your pure water to waste water ratio should be about 1 to 4. Should be easy to tell that way which is the pure water out & which is the waste, since the output will vary significantly between the two. That is, the water coming out of the waste line should be running much faster than the pure water out.

I've seen quite a few posts about water quality at various locations around our fair country & you folks in greater Van have some of the best source water anywhere, usually less than 10 TDS, so the 300 you're seeing is really wacky. Some areas like White Rock are on a different source & TDS may be somewhat higher but still nothing like what we have in the North Okanagan. My incoming TDS is usually close to 200 & my 75 gpd membrane gets that down to 1 TDS after running for about 5 minutes. Which reminds me to ask, what's your water pressure? Water pressure & temperature both have a major effect as to the efficiency of an RO system. If there's a way for you to disconnect your TDS probe & hold it under running tap water, you'll know what your incoming TDS is. Water quality reports available from your supplier are also a good source of info on your incoming water.

As someone has already mentioned, over 300 TDS for your area is out to lunch. It's possible your sediment filter may be releasing all that TDS into the system, but after running 6-8 hours it should have come down significantly provided the system is hooked up properly.

Let us know how you make out after disassembling the unit. It would be a shame to toss it & buy another without further troubleshooting. Like you said, it's not rocket science & if assembled in the correct order with serviceable components, there's no difference between a generic, vertex, brs, or what have you system. They're all built with more or less generic components. Some have a few more bells & whistles, but the real difference is generally in the quality of the membrane & carbon blocks.

Ryanerickson
05-19-2013, 04:20 PM
I had a issue like this it ended up I had had di balls that was exhausted in my last pre filter but I figured it out by putting the line coming from tap directly into the ro then tested water that came out it was 0. What is the problem with di balls before ro? Will it make the life of my ro membrane shorter? I thought it would help it last longer because water coming out of pre filter is coming out at 1 ppm then it goes into ro any one know ? Thanks

11purewater
05-19-2013, 04:30 PM
The DI is there to filter the Ro product water to 0 TDS(non conductive) if you can't achieve it with the RO membrane alone.For example 200 TDS feed water going through a membrane @ 98% rejection=4PPM product water,DI after brings it to Zero.

hillegom
05-19-2013, 08:25 PM
The DI is there to filter the Ro product water to 0 TDS(non conductive) if you can't achieve it with the RO membrane alone.For example 200 TDS feed water going through a membrane @ 98% rejection=4PPM product water,DI after brings it to Zero.

I agree. The DI is the most expensive, and it should be last. You try to get the lowest TDS out of your system that you can and then send it to the DI where it will come out at 0 TDS.
If after the DI, it is not 0 then the DI is exhausted and you need to replace it.

neoh
05-19-2013, 09:17 PM
How old or new are the filter media?

Don't know!


You can flush it by temporarily removing the restrictor on the waste line. Do you have a pic of that?

During the time of high TDS, I did not have the restrictor on the waste line.

That's a great idea, particularly if you have little to no information as to filter media condition from the previous owner. It could well have been sitting for some time, either dry or wet & has all kinds of nasty stuff bound in the sediment and/or carbon stages. The membrane could also be shot if it has dried out.

I know on my system, the center fitting out of the membrane is the pure water & the waste is the outer fitting & that's usually the way most membrane housings work, but one never knows for sure without confirmation of the manufacturer or by opening it up. The way most membranes are built, the water is pushed from the outside to the inside while flush water rinses the outside of the membrane. So it makes sense that the center fitting on the membrane is the pure water.

Also make sure there is a restrictor on the waste line somewhere. Some are built into the waste line fitting, some are obvious combination valve/restrictor units that you can use to either flush the membrane or produce pure water by closing the valve. With the restrictor in line & working properly, your pure water to waste water ratio should be about 1 to 4. Should be easy to tell that way which is the pure water out & which is the waste, since the output will vary significantly between the two. That is, the water coming out of the waste line should be running much faster than the pure water out.

I've seen quite a few posts about water quality at various locations around our fair country & you folks in greater Van have some of the best source water anywhere, usually less than 10 TDS, so the 300 you're seeing is really wacky. Some areas like White Rock are on a different source & TDS may be somewhat higher but still nothing like what we have in the North Okanagan. My incoming TDS is usually close to 200 & my 75 gpd membrane gets that down to 1 TDS after running for about 5 minutes. Which reminds me to ask, what's your water pressure? Water pressure & temperature both have a major effect as to the efficiency of an RO system. If there's a way for you to disconnect your TDS probe & hold it under running tap water, you'll know what your incoming TDS is. Water quality reports available from your supplier are also a good source of info on your incoming water.

As someone has already mentioned, over 300 TDS for your area is out to lunch. It's possible your sediment filter may be releasing all that TDS into the system, but after running 6-8 hours it should have come down significantly provided the system is hooked up properly.

Let us know how you make out after disassembling the unit. It would be a shame to toss it & buy another without further troubleshooting. Like you said, it's not rocket science & if assembled in the correct order with serviceable components, there's no difference between a generic, vertex, brs, or what have you system. They're all built with more or less generic components. Some have a few more bells & whistles, but the real difference is generally in the quality of the membrane & carbon blocks.

As mentioned previous, I did not have a restrictor on the waste line during the high reading stage.

This morning I took the third filter media apart and took a look inside. Now, I have no idea what the inside of a DI filter looks like, so I'm going to assume this is it:

http://imageshack.us/a/img705/4104/20130519130222.jpg

(The last one on the right there) - taking apart of the bottom of that filter, it seems to be filled with a small roe-like substance, and since I know it's not carbon, and chances are not likely to be sediment. I'm going to assume this is the DI portion.

I hooked up the tap water right into the unit and out. My TDS is different in the morning as it is at night (for whatever reason that is) - and out of the tap it's reading 8, and out of what appears to be the DI portion - I'm getting a 0 reading.

http://imageshack.us/a/img856/4715/20130519130647.jpg

So, I'm going to hook everything back up - with the restrictor on the waste line, and run it through sediment - carbon - membrane - di - bucket, and see what happens.

hillegom
05-19-2013, 09:42 PM
Of the pic with the 3 filters, the one on the rt is the DI. Your sediment filter on left looks like it could be replaced. Should be white when new, looks to have particles, (brown) all over it.
Do you have a pressure gauge? If so you could hook it up after the carbon filter and then to before the first, sediment filter and compare readings. If you have at least 60 psi at both places, the filters are still good.

The path of the water in your system should be:
sediment, carbon, RO membrane, DI. Most systems have two carbon filters to ensure the RO membrane does not receive any chlorine, which deteriorates the RO membrane.

The following in no way promotes this co. I have never bought from them, but the diagram on page 8 might help you. In your case, the 5th stage would be the DI
http://www.watergeneral.com/support/pdf/RO585.pdf

scherzo
05-19-2013, 11:00 PM
If you ran it without the restrictor. Then the unit isn't actually ON.

For the RO membrane to produce pure water you have to have the restrictor ON.

If you don't get 0 out of the RO membrane then you need a new RO membrane.

As others have said, you'll need to get a new sediment and carbon block (from the looks of the pic)

neoh
05-19-2013, 11:46 PM
I will get a new carbon and sediment block. The restrictor is now on the waste line, and I'm getting 0 TDS out, very - very slowly. Waste water is dumping fine, but the good water is about 1 drop every 10 seconds or so. I don't have a gauge to measure the pressure.