TFC membrane stilll good?

[Klaus777]

So I have had the same membranes (dual, connected in series) in my R.O. unit for more than 8 years now. My incoming TDS measures near 400pmm and outgoing around 3ppm before DI.
My concern is an issue with cyano, dinos, and hair algae that despite frequent water changes and over all maintenance is showing no signs of improvement.
I'm wondering if there is a fouling issue with the membranes that can be causing this, is that even possible?
I realize that its recommended to change the membranes after a couple of years but with the TDS keeping in check I didn't bother with replacement.

 

[Sandybw1]

So I have had the same membranes (dual, connected in series) in my R.O. unit for more than 8 years now. My incoming TDS measures near 400pmm and outgoing around 3ppm before DI.
My concern is an issue with cyano, dinos, and hair algae that despite frequent water changes and over all maintenance is showing no signs of improvement.
I'm wondering if there is a fouling issue with the membranes that can be causing this, is that even possible?
I realize that its recommended to change the membranes after a couple of years but with the TDS keeping in check I didn't bother with replacement.

Following. I have the same issue with cyano

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[Buckeye Hydro]

When membranes go bad, you'll see one or both of two things:
1. The TDS of the permeate (RO water) isn't as low as it should be. Meaning that the membrane(s) are not cleaning the water to the extent they should.
2. The membrane(s) are not producing permeate (RO water) as fast as they should, once you've adjusted for your water pressure and your water temperature. You can use our calculator to do this.

Russ