[herbiefatboy]

this question has i am sure been asked before but how long do the membrane in 100gpd   300gpd  with a high tds last a rough guide would be great thanks

[Ian Lancaster]

Depends how you look after them.  With a decent booster pump and regular flushing/prefilter changes, my 300gpd RO-man lasted 3 years, then I sold it and it's still going strong on the original membranes.

[herbiefatboy]

thanks for your help

[herbiefatboy]

also what are the signs to tell your they need changing.

[mark dew]

my 300gpd ro membranes have lasted 2 years now. Changed the prefilters after 18 months cos the tds started rising. New filters and good as before.
I assume you will know when membranes need replacing when tds rises and new filters don't make a difference.

[windowwashers]

my 300gpd ro membranes have lasted 2 years now. Changed the prefilters after 18 months cos the tds started rising. New filters and good as before.
I assume you will know when membranes need replacing when tds rises and new filters don't make a difference.

18 months on pre filters 

I change mine monthly

[frames to panes]

  monthly why

[windowwashers]

monthly why

because I can 

Only joking
I have loads of filters, a box full, my water is very bad out of tap, it is not bang on a month but not far wrong, I do this as I use alot of water and I want to protect the membrane in my 4040

[frames to panes]

Blimey, how often do you change your engine oil?

[brightnclean]

OMG @ 18 months beteween filter changes!!! 

If ur membranes aren't knackered ur very.. very lucky.

The carbon ones are there to take chlorine outta the water coz it damages RO membranes. The signs that membranes have had it is lower and lower  output and higher and higher TDS out. How do I know?  Coz I ruined a 40 inch membrane by not changing the pre filters

Ian aint overdoing it..  didn't u buy a great stack of cheapo ones Ian? I am not saying they are crap but u paid next to nowt for em as I remember in a thread a while back?

[windowwashers]

OMG @ 18 months beteween filter changes!!! 

If ur membranes aren't knackered ur very.. very lucky.

The carbon ones are there to take chlorine outta the water coz it damages RO membranes. The signs that membranes have had it is lower and lower  output and higher and higher TDS out. How do I know?  Coz I ruined a 40 inch membrane by not changing the pre filters

Ian aint overdoing it..  didn't u buy a great stack of cheapo ones Ian? I am not saying they are crap but u paid next to nowt for em as I remember in a thread a while back?

you are right I did a box full, and they are just as good as the others to be honest