I've stripped back the RO to a single 100 gpd membrane, removed the resin and measure the output from both the old and the new membranes.
Lesson learned: always test before upgrading. The old membrane, albeit less than a year old, is clearly a significant part of the problem with an output of 063 ppm. I’m not really sure what has caused this because I definitely change the pre filters every 6 to 8 weeks and I flush the system regularly. I’d really like to get to the bottom of this and would appreciate any thoughts?
To qualify, the RO system is 2½ years old and has 2 pre filters.
- I usually buy my prefilters from cleaningspot.co.uk as I like their free delivery option if you spend £45 and the fact they use DPD, who send me a text with an hour delivery window on the morning of delivery.
The filters I buy are: a 10" Cartridge sediment filter 5 microns and a 10" Cartridge carbon block filter 5mic. Please can someone confirm I am buying the correct pre filters?
- note: The 10" Cartridge sediment filter 5 microns I used to get from cleaningspot were very tightly wound and in a tight fitting cellophane wrapper. More recently they have been sending me less tightly wound 10" Cartridge sediment filter 5 microns in a paper wrapper, which I don’t think are as good?
With the new housing and membrane the TDS drops to between 011-012 ppm, which is much better and is around what I remember after testing when the system was new
(or after fitting a new membrane). I've got another new 100 gpd membrane arriving on Monday, so with this fitted I can re-upgrade to 200 gpd and I should expect a similar reading prior to resin?
I’m a little concerned that my readings are almost double those that Alex and dd suggest I should be getting. I’m wondering if
‘like for like’ is being compared because I’ve noticed there are some RO systems with a third pre filter? I currently have inline a 550 rated flow restrictor, could this have much bearing?
I’ve tested my tap water pressure again to day and it’s 44 psi. My pump says it requires an input of a minimum of 35 psi, so that should be OK. The pump says it delivers a working pressure of 100 psi, so that should be OK too and although I don’t have any means to test it, it appears to be working fine.
From the picture included in my first post, have I fitted the upgrade correctly to minimise waste water?
Any thoughts, suggestions, criticisms and pictures of lewd women are very much appreciated.
Duncan