RODI Question

[Trey]

Ok so I have this older RODI system that I have been using for years. The DI is currently disconnected and I use it for drinking water for myself and my other animals, as well as to fill the pond in my basement. Can/ should I hook it up to my new RODI system? Check out the pics and thanks!

 

[ThePickeledReef]

I like the new system! Idk about making a super stage system... will you take booster pumps and Pressure gauge over

 

[1ByLand2BySea]

It seems your new RO is a 7 stage system, including 3 DI modules. I am not sure what else can adding the 2 additional modules do for you.
The new system looks good!

 

[Trey]

It seems your new RO is a 7 stage system, including 3 DI modules. I am not sure what else can adding the 2 additional modules do for you.
The new system looks good!

Thanks for the input, the old system is also a seven stage with two ro membranes and two pre filters/ two carbon blocks... just not sure if I can integrate the two for longer filter/membrane life..?

 

[1ByLand2BySea]

Thanks for the input, the old system is also a seven stage with two ro membranes and two pre filters/ two carbon blocks... just not sure if I can integrate the two for longer filter/membrane life..?

2 things that kills the RO membrane are Warm water from the source (usually not an issue) and chlorine in the water source. just use good quality carbon block cartridges or ones that are rated to remove chloramine. They are considered to last longer and have a higher capacity to remove the chlorine from the tap water. 2 Modules for carbon are generally more than sufficient.

Having more that one sediment cartridge does not add additional level of protection unless you have major issues with sediments from the water source. In that case you can have 2 sediment modules, one with 5 micron and one with 1 micron cartridge.

You also have 3 DI modules, you can have several combination of DI cartridges to polish the product water that covers everything for you.

I am not sure if your new system has a back flush. If not, I would strongly suggest getting one as it will increase the efficiency and life of the membrane. You should be all good IMO.

 

[Trey]

2 things that kills the RO membrane are Warm water from the source (usually not an issue) and chlorine in the water source. just use good quality carbon block cartridges or ones that are rated to remove chloramine. They are considered to last longer and have a higher capacity to remove the chlorine from the tap water. 2 Modules for carbon are generally more than sufficient.

Having more that one sediment cartridge does not add additional level of protection unless you have major issues with sediments from the water source. In that case you can have 2 sediment modules, one with 5 micron and one with 1 micron cartridge.

You also have 3 DI modules, you can have several combination of DI cartridges to polish the product water that covers everything for you.

I am not sure if your new system has a back flush. If not, I would strongly suggest getting one as it will increase the efficiency and life of the membrane. You should be all good IMO.

Is a back flush the same a a ro membrane flush valve? If so both units have them. Can’t say I’ve ever used it.. maybe you can enlighten me on when it would be appropriate to do so.. and how?

 

[1ByLand2BySea]

Is a back flush the same a a ro membrane flush valve? If so both units have them. Can’t say I’ve ever used it.. maybe you can enlighten me on when it would be appropriate to do so.. and how?

I am sorry it is called a flush valve. It bypasses the flow restrictor and lets full pressure and flow of prefiltered water after the last carbon module to rinse off the surface of membrane from any residue/built up. It should be used every time you replace the sediment and carbon block cartridges to prevent the carbon dust to settle on the membrane as well as letting the trapped air to scape the system faster. Ideally it also should be used prior to every water making but I personally open the flush valve for a minutes and couple of times a months.
Please be aware that whenever you open the flush valve, almost all the water that enters the system will be end up in the waste line and almost no RO water will be made. Once you close the flush valve, it will pressurize the membrane and it will go back to normal.

 

[Opus]

I will disagree on the flush valve theory. There is no data to prove that it actually prolongs the life of the ro membrane in a consumer setting. Yes, when you get new prefilters, you should run each one separately for several minutes to remove any lose particles that are there from manufacturing and shipping. As long as you don't let chlorine thru to the ro membrane it should last 5 to 7 years depending on your water source. My source water is usually over 400 tds and mine last 5+ years.

 

[KStatefan]

I agree with the flush valve not doing anything in most cases if you are running the system at close to standard rejection rates.

 

[1ByLand2BySea]

Flush valve is a standard practice in RO technology and not a theory. Over time very small particles (below 0.5 micron) will settle on the membrane film which over a course of a time reduces the rejection rate. Without flushing the membrane the quality of membrane will be diminished over time. This is not about how long the membrane could last and more about how well the membrane will work for you over its life.
All professional RO units are equipped with electronic flush switch prior to each use and at regular intervals for this reason. We are not making water for our fish tanks at industrial levels but the science and technology is relative and applies.

 

[Opus]

Flush valve is a standard practice in RO technology and not a theory. Over time very small particles (below 0.5 micron) will settle on the membrane film which over a course of a time reduces the rejection rate. Without flushing the membrane the quality of membrane will be diminished over time. This is not about how long the membrane could last and more about how well the membrane will work for you over its life.
All professional RO units are equipped with electronic flush switch prior to each use and at regular intervals for this reason. We are not making water for our fish tanks at industrial levels but the science and technology is relative and applies.

Since I base how long the membrane will last on its efficiency, it would effect how long it lasts and in my case I don't believe it does. I want mine to be running at 98%+ efficiency or it will be replaced. I get 5 to 7 years out of mine without flushing. So all that time and water i waste flushing over those 7 years, will that get an extra month, 3 months, 6 months, no month?

 

[1ByLand2BySea]

Efficiency of a membrane is not consistent from first to the its last day of life at any conditions. Its efficiency starts to decline slowly and gradually from day 1 and over the course of its life. Although its a matter of individual choice what rate is acceptable before the membrane is replaced, it does not take long within its life that the efficiency rate is below 98% and by the end of it will be way below that. Over the course of its life, the little water that will be used to flush the membrane 1-2 minutes a month is always far less than the water that will be saved by reduced rejection rate over the the life of the membrane. Clearly a higher rejection rate over longer period of time translates to making the DI cartridges last longer in our aquarium keeping world.
There are many factors involved to determine the life and efficiency of RO membrane including individual usage but the principal remains the same. But flushing the membrane is just a maintenace involved to keep your membrane at its best shape and as long as you can.

 

[Opus]

We will just have to disagree. Until someone can point me to data that proves it actually makes a difference in the long run, I will never do it. I've talked to people in the water industry that I trust and they have told me on consumer units like ours they do not believe it makes any difference. If I'm getting 99% rejection rate on day 1 and after 5 years I'm at 99 or 98 then I'm happy.