Ro/di filter replacement when?

[Terry Mattson]

I have a 5 stage ro/di system. My tds now reads 1 coming out the end. It has been a year. Typically my input runs 270, I use about 60 gallons a month. I have a tds meter at 4 points. Not sure where the middle two are. But new they were 270, 4, 0, 0. Now 270, 4 to 6, 2, 1?

 

[LiveWire]

It really depends on what rejection rate your membrane is as well as if you have any pressure drop. A TDS of a a couple points is no reason to freak out as it is still very clean water but if your membrane has been exposed to a lot of chlorine it will greatly reduce its lifespan. You can test the waste water to determine how your membrane is preforming as well as knowing the rejection rate of the membrane and then taking the inlet TDS and subtracting that from the permeate TDS after the membrane. I have TDS meters all throughout my system so that i can monitor whats going in and out of each one. I also have placed sediment filters behind my carbon blocks to protect the membrane. There are some great Videos online from BRS that can help you and give you some guidelines as well. Hope this helps out.

 

[LiveWire]

 

[Terry Mattson]

It really depends on what rejection rate your membrane is as well as if you have any pressure drop. A TDS of a a couple points is no reason to freak out as it is still very clean water but if your membrane has been exposed to a lot of chlorine it will greatly reduce its lifespan. You can test the waste water to determine how your membrane is preforming as well as knowing the rejection rate of the membrane and then taking the inlet TDS and subtracting that from the permeate TDS after the membrane. I have TDS meters all throughout my system so that i can monitor whats going in and out of each one. I also have placed sediment filters behind my carbon blocks to protect the membrane. There are some great Videos online from BRS that can help you and give you some guidelines as well. Hope this helps out.

Very helpful. Thanks. I run a pump to raise psi to 80 from 50 psi. This pump is designed for this ro/di system. The one thing I discovered is ammonia <.25 but not Zero, is in my ro/di water output from the system. Some how this is getting through. Could of been since day 1.... any thoughts?

 

[LiveWire]

Most likely you have chloramines in your water supply and it may be as simple as you need to use a better carbon filter that will take care of that like the BRS universal. Could also be the sizing of your RO unit and or the restrictor that is put in line the waste water line. If you only use 60 gallons a month then a smaller GPD unit would be your best option as the best thing for your RO system is to let it run so if you have a 100 GPD unit you may be only running it for a short amount of time and then shutting it off.

Raising your pressure from 50 to 80 is a great start and will make your unit work much more efficient. Have you tested your ammonia going into the first stage? What size unit are you running, and what brand membrane are you using? Do you happen to know the rejection rate? and are you flushing the membrane out at all before each use, and how often are you going through DI resin?

 

[Quietman]

I'm confused...where are you measuring 1ppm TDS? Out put of RO or total system?

 

[Quietman]

I have a 5 stage ro/di system. My tds now reads 1 coming out the end. It has been a year. Typically my input runs 270, I use about 60 gallons a month. I have a tds meter at 4 points. Not sure where the middle two are. But new they were 270, 4, 0, 0. Now 270, 4 to 6, 2, 1?

Ah I see here. I don't think that's your RO. 270 is input so your RO until will be doing it's job even at 5% which is 13 ppm TDS. So it's just a bit normal aging. I assume the 2, 1 are your DI media outputs.

@LiveWire ...yes? Am i missing something fundamental?

 

[Terry Mattson]

I am going to pull out manual tonight and get more information on rejection rate and placement of the 4 tds meters ... Retested ammonia levels at source, ro/di fresh, and mixed new saltwater and now I am getting zero for all three. Our community is on it's own well. I did look at the water report and it said uses clorine. The water is soft based on test strips provided by Spectra Pure. The unit I have is 90 GPD. Will advise on more information later. Recovery from radiation therapy to zap my cancer.

 

[Dr. Dendrostein]

I have a 5 stage ro/di system. My tds now reads 1 coming out the end. It has been a year. Typically my input runs 270, I use about 60 gallons a month. I have a tds meter at 4 points. Not sure where the middle two are. But new they were 270, 4, 0, 0. Now 270, 4 to 6, 2, 1?

Need to consider first does the house have a water softener, if no, then I would change it every two years your RO membrane. If the house has a water softener then every 5 years. All the other pre filters follow manufacturer recommendation and your tds meter

 

[Fishingandreefing]

I had mine since April of 2018 and it’s currently reading TDS 5. Recently changed the carbon and sediment. Think it’s my time to replace the ro and membrane.