RO problem

[Ice Man]

What can cause sudden TDS spike right after turning on the water? Inline TDS meter is showing increase up to 250 TDS. It goes down after a minute, but never to the same level. Every day average TDS reading is increasing. Right now it is at 70 TDS. Already replaced 3 membranes, ASOV and flow restrictor. Every time it works fine for a month and then TDS reading starts increasing.
Tap water TDS is around 750. Purified water TDS was around 20 with new membrane and only after one month of use it jumped to 70. Any ideas what can be wrong with RO system?

 

[pcdebb]

from what I understand, the TDS reading will have a high reading when you first run it, then it goes down. Mine does this and I called BRS and they told me this is normal. Is this what you are seeing?

 

[Ice Man]

This is exactly what happens! But every time it happens TDS never go down to the same low number. So right now after it spikes TDS only goes down to 70.

 

[pcdebb]

I think there is a problem here then. I have "in" and "out" and my out always goes down to like 3 (again, they said normal). 70 is too high IMO.

I also thought that the membrane is the one that rarely gets replaced. Have you tried replacing the cheaper filters? try replacing the sediment or carbon. if you have DI resin, what does that look like?

 

[Mrc8858]

Are you flushing your membrane periodically? You may be getting some build up on it which would explain why after each use the starting TDS is higher each time.

 

[Ice Man]

Are you flushing your membrane periodically? You may be getting some build up on it which would explain why after each use the starting TDS is higher each time.

Membrane gets flushed once a week for at least 15-20 minutes. I don't use more than 15 gallons of water per week. I also noticed that system sometimes dumps water into drain line even when when I don't use it.

 

[Ice Man]

I think there is a problem here then. I have "in" and "out" and my out always goes down to like 3 (again, they said normal). 70 is too high IMO.

I also thought that the membrane is the one that rarely gets replaced. Have you tried replacing the cheaper filters? try replacing the sediment or carbon. if you have DI resin, what does that look like?

I replaced all filters, sediment and two carbon, last time I replaced a membrane, about 3 months ago. Sediment filter is still clean because I only use around 15 gallons of water a week. DI filter got depleted very quickly, producing no more than 80 gallons of water.
Yesterday I removed and reinstalled the membrane. It helped for a while producing 20 TDS water but today TDS is all the way to 90.
I am frustrated!!!

 

[Mrc8858]

You may have a pressure issue it sounds like. Do you have a psi gauge?

 

[Ice Man]

You may have a pressure issue it sounds like. Do you have a psi gauge?

Pressure is at 55psi

 

[Mrc8858]

That's a little low but not enough that it should be causing it to under perform that much imo. I'm stumped... Maybe your tap TDS is just so high that it has to work that much harder to purify it.

 

[Ice Man]

I honestly don't know what is wrong. I replaced almost every single bit of this ro system and still get the same symptoms. I replaced ro membrane, membrane housing, flow restrictor, asov and pre filters. I am ready to give up.
I guess that is what happens when you buy cheap stuff.