http://www.collinswaterproductsltd.co.uk/ourshop/prod_6274199-Hid-LOW-PRESSURE-4040-commercial-reverse-osmosis-membrane.html Has anyone tried these as previously mentioned Collins water
Here's the spec on the link you provided.
HID commercial
LOW PRESSURE 4040 reverse osmosis membrane
HID RT-40/40 LP -
cheap Chinese manufacture.THIS IS A HIGH FLOW MEMBRANE
WITH REDUCTION RATES OF 90% TO 98%
98% is good - 94% is generally the recommended time to replace the membrane as resin costs make it uneconomical to continue - 90% its got even worse. The optimum working pressure for this membrane is 140psi -
that's low pressure compared to a desalination membrane that operates at around 600psi. We can't get a booster pump up there. We have extensively tested our membranes and achieve the following test results:
Test parameters
Mains water input pressure 75psi -
is your water pressure this high? You will need a booster pump.input water tds reading 274ppm
With the above parameters test results achieved are
production 2.7ltrs per min
output tds reading 8ppm or less -
what is it? A membrane gets down to a certain rejection rate and stays there which should have happened during the test. According to this they achieved 97% rejection rate at half the optimum water pressure. Something just doesn't sound right to me.Quite a while back one of the suppliers stated that the Chinese manufacturer of HID membranes 'copied and pasted' word for word the specs from an Axeon membrane for their own product specs. The Chinese as good at that.
I have nothing against Collins Water BTW.
They have been in business for a long time. However, it has only been in the recent past that they have added window cleaning to their supply list of uses/users of their products.