[paul saunders]

Has anyone tested their TDS after the pre filters but before the RO membrane. I tested mine today and it was the same as the TDS from the tap. If this is right, what exactly do the pre filter remove.
Also, how do you know when to change the RO membrane. Mine is still producing 000 but the output has dropped by almost 50%.

[[GQC] Tim]

Has anyone tested their TDS after the pre filters but before the RO membrane. I tested mine today and it was the same as the TDS from the tap. If this is right, what exactly do the pre filter remove.
Also, how do you know when to change the RO membrane. Mine is still producing 000 but the output has dropped by almost 50%.

Prefilters remove sediment and chorine (other stuff as well, but thats the majority.)

Both are not water soluble, hence the total disolved solid rating stays the same.

[Rob.Hall]

If my output drops I change the filters and that seems to work.

I also change the resin if the tds starts to go above 3.