Using RODI water

[Shawn_epicurious]

I am using a standard 4 stage RODI system and I am somewhat unhappy with its performance. I recently changed the lower 3 filters. I’ve had at most, 250 gallons of water go thru it and now my TDS is already up to 2.

Is that normal? And if it is, do I need to replace all 3 filters again already? Or is one of these filters more important than the other 3?

 

[Brandon Smith]

How old is the RO membrane? Are you sure the filters are installed in the correct order? Have you tried flushing your RO membrane?

 

[WIReefer]

I am using a standard 4 stage RODI system and I am somewhat unhappy with its performance. I recently changed the lower 3 filters. I’ve had at most, 250 gallons of water go thru it and now my TDS is already up to 2.

Is that normal? And if it is, do I need to replace all 3 filters again already? Or is one of these filters more important than the other 3?

Are you flushing the system before each use this can be a simple tds creap that you are seeing.

 

[Antics]

How high is the source water TDS?

 

[Saltyreef]

Co2 could be your issue. I was burning through more resin than this.

It was a simple fix.

I pump my RO water straight into a 20gal brute, then let it mix with an mj900 pump and airstone overnight to get rid of the excess c02.

The next day i hook up an mj1200 and pump the RO watee through my DI resins.

My first stage was showing 2 tds and now after this new offgassing method, it shows only 1 tds on the same batch of resin.
Final stage 0.

 

[Shawn_epicurious]

How old is the RO membrane? Are you sure the filters are installed in the correct order? Have you tried flushing your RO membrane?

I replaced all three of the lower filters, including the RO membrane 3 weeks ago.

 

[Shawn_epicurious]

Are you flushing the system before each use this can be a simple tds creap that you are seeing.

About to learn something new here... “flushing” the system? I do not know what you mean.

 

[Shawn_epicurious]

How high is the source water TDS?

I just measured the source water at 188

 

[Pistondog]

I am using a standard 4 stage RODI system and I am somewhat unhappy with its performance. I recently changed the lower 3 filters. I’ve had at most, 250 gallons of water go thru it and now my TDS is already up to 2.

Is that normal? And if it is, do I need to replace all 3 filters again already? Or is one of these filters more important than the other 3?

Bought several rodi systems from Amazon and was not happy. Like you said flow changes or tds. Recently purchased brs 4 stage value system. Higher output, integrated tds and flushing valve for membrane. Did I say it was more efficient; less waste water. They are in it for the long haul.

 

[Brandon Smith]

You should have a flush vavle by your RO membrane. Usually it is white with a black lever. I forget how ling to flush it for, but I would do at least 25 mins

 

[Shawn_epicurious]

Co2 could be your issue. I was burning through more resin than this.

It was a simple fix.

I pump my RO water straight into a 20gal brute, then let it mix with an mj900 pump and airstone overnight to get rid of the excess c02.

The next day i hook up an mj1200 and pump the RO watee through my DI resins.

My first stage was showing 2 tds and now after this new offgassing method, it shows only 1 tds on the same batch of resin.
Final stage 0.

I have not tried using an air stone. Instead I have been hanging my hose on the side of the barrel and then let the pump run to circulate the water. I assumed the water splashing down from above was enough to aerate the water

 

[KStatefan]

About to learn something new here... “flushing” the system? I do not know what you mean.

You can learn a lot from this thread by Russ @Buckeye Hydro

Let's Talk RO & RODI

I wanted to introduce, or re-introduce some common jargon pertaining to RO and RODI systems that few people in the hobby commonly use. PERMEATE - the water that has made its way through the RO membrane. Often called "RO water." In most situations, the TDS of permeate should be 5% or less of...

www.reef2reef.com

 

[Pistondog]

Co2 could be your issue. I was burning through more resin than this.

It was a simple fix.

I pump my RO water straight into a 20gal brute, then let it mix with an mj900 pump and airstone overnight to get rid of the excess c02.

The next day i hook up an mj1200 and pump the RO watee through my DI resins.

My first stage was showing 2 tds and now after this new offgassing method, it shows only 1 tds on the same batch of resin.
Final stage 0.

Do you mean excess co2 in the tap water?

 

[Shawn_epicurious]

Bought several rodi systems from Amazon and was not happy. Like you said flow changes or tds. Recently purchased brs 4 stage value system. Higher output, integrated tds and flushing valve for membrane. Did I say it was more efficient; less waste water. They are in it for the long haul.

You are saying a need a better system? That is entirely possible. Mine does not have a manual switch for flushing. It appears to be happening on some type of automated basis. There is a return line going back to the drain, but it is not operated by a switch.

 

[Saltyreef]

Do you mean excess co2 in the tap water?

Yes

 

[Saltyreef]

And a 3 way valve/di bypass valve is what you want. A flush valve is highly debated.

The DI bypass valve flushes the TDS creep out of the outlet side of the RO membrane before it reaches the resin where the flush valve does not. So all that tds creep ends up prematurely wasting your DI resins.

 

[Saltyreef]

Heres my setup.

Spectrapure 5 stage. Ignore tubing color. I use whatever, whereever lol

 

[Biglew11]

What is your tds right after the membrane? Decent membranes will filter between 96 to 99 percent. Like another poster said you want to direct the first 5 or so minutes of the membranes product water to remove the tds creep. I run mine until I see about 4 tds. Then close the valves and let that through the di resin.
Not flushing the tds creep will deplete your di resin fast as the first few minutes can actually be higher than your source water.

I also flush mine around 5 minutes on startup. this bypasses the flow restrictor allowing full flow to allegedly wash any junk off the ro membrane.

Someone else mentioned co2 in the source water I have no experience on this but it can alsobe an issue. It seems Most people withthis issue stores the product water right off the ro membrane in a container to out gas and then pump this water slowly through the di ressin into a separate container.

Edit if you have low tds right off the membrane and still depleting di resin fast you likely have co2 in source water.

 

[Shawn_epicurious]

Bought several rodi systems from Amazon and was not happy. Like you said flow changes or tds. Recently purchased brs 4 stage value system. Higher output, integrated tds and flushing valve for membrane. Did I say it was more efficient; less waste water. They are in it for the long haul.

Problem solved. Thanks for the advice. I just got this...

7 Stage Pro Plus RO/DI System - Bulk Reef Supply

Why Does BRS Recommend This? If you have hard to remove contaminants, your city uses chloramines, or you just are not sure what is in your water the BRS 7 Stage Pro Plus RO/DI system is the perfect solution to make ultra-pure water for your saltwater aquarium. The Triple DI Saver system uses...

www.bulkreefsupply.com

 

[Shawn_epicurious]

What is your tds right after the membrane? Decent membranes will filter between 96 to 99 percent. Like another poster said you want to direct the first 5 or so minutes of the membranes product water to remove the tds creep. I run mine until I see about 4 tds. Then close the valves and let that through the di resin.
Not flushing the tds creep will deplete your di resin fast as the first few minutes can actually be higher than your source water.

I also flush mine around 5 minutes on startup. this bypasses the flow restrictor allowing full flow to allegedly wash any junk off the ro membrane.

Someone else mentioned co2 in the source water I have no experience on this but it can alsobe an issue. It seems Most people withthis issue stores the product water right off the ro membrane in a container to out gas and then pump this water slowly through the di ressin into a separate container.

Edit if you have low tds right off the membrane and still depleting di resin fast you likely have co2 in source water.

The system I have doesn’t have an inline TDS meter or a valve for flushing. I just bought a really nice new system from BRS.