[Small but perfectley formed]

who uses these are they better than older type membranes.
Had to buy 2 for the IPC Eagle 

[Spruce]

If you mean the difference between the HF4 and HF5 then they are just as good as each other in their particular working environment.

HF5 is supposed to work better at lower water pressures than the HF4. I have an HF5 and it works perfectly at our water pressure of 50psi without a booster pump.

If you are using a booster pump then I'm told the HF4 is more suited to those pressures.

A fellow window cleaner in our town has an HF4 in his Pure Freedom r/o and his works as well as mine does. They do have a better water pressure though.

PF did tell me that at 40psi there was no difference in performance between the HF4 and HF5, but I went with my gut feel and bought the more expensive HF5 to be sure. I've run it for 18 months now. Our water tds varies between 100 and 125. This membrane gets the tds down to around 1 to 2.

When you have to replace two membranes, that's a bad month expenses wise.

[Paul Coleman]

I use HF5 @ 35-40 PSI.
It's still turning out water at 008 TDS after 3 years (I flush once or twice per week and have waste:pure around 50:50ish).  Production isn't particularly quick for such a membrane though - about 1ltr/min spring to autumn and a bit less when it's cold.

[Small but perfectley formed]

 Well i have replaced them and production has now reached 6 Lt per min ,

[easy clean]

David,

What is your input Tds?