Problem with new RODI membrane

[juboy27]

I’ve bought 2x 75-gallon membranes to replace my old ones.

The problem I’m having is that I’m now getting a high TDS reading of 20 after the new membranes.

The TDS going into the membranes from the house is 340 tds

My old membranes used to bring it down to 10 TDS coming out of them, not 20.

My booster pump is running at about 35 PSI, which my old membranes were fine on.

I can’t work this out. I’ve left them flushing and rinsing through for hours.

Can anyone help?

Thanks

 

[Justfebreezeit]

First thought is psi to low. I get 60ish with no issues. Drops my tds down to 5 or 6 from 100ish

Just because your previous membranes handled low psi for some reason dosen't eliminate that from why the current ones are having an issue imo

 

[juboy27]

First thought is psi to low. I get 60ish with no issues. Drops my tds down to 5 or 6 from 100ish

The pump is very old so I best get a new boost Pump ? To achieve the 60 psi.

 

[slingfox]

Are your sediment filter and carbon blocks also relatively new? If they get clogged then that reduces PSI as well.

 

[BeanAnimal]

If they are both Dow Filmtec's then both are running within spec. 94.1% vs 97%


I think dow lists 94% min and 98% max at 50 psi 77 F°

35 PSI is low. Any booster should put you at 65 to 85. Are you sure?

Also if the old membranes were at 10 out, why did you replace them?

 

[juboy27]

Are your sediment filter and carbon blocks also relatively new? If they get clogged then that reduces PSI as well.

The sediment filter and carbon filters are brand-new replace them the same time as the membrane so the only part that isn’t new is my 16 year-old pump

 

[juboy27]

If they are both Dow Filmtec's then both are running within spec. 94.1% vs 97%


I think dow lists 94% min and 98% max at 50 psi 77 F°

35 PSI is low. Any booster should put you at 65 to 85. Are you sure?

Also if the old membranes were at 10 out, why did you replace them?

I wanted to replace them because they are roughly about 2 1/2 years old and I’m having some issues in the tank so I went back to My source water which is my RODI unit and wanted to make sure that was on Point