I am preparing to get an under-sink RO system with pressurized storage tank for
both drinking and aquarium use, and have a question about the auto shut-off
(ASO) valves included in most systems.
When the ASO valve is activated it shuts down the input to the RO cartridge and
causes the pressure differential across the membrane to decrease (and maybe even
reverse). If residual water remains in the cartridge, will this situation allow
any significant amout of impurities to pass from the "dirty" side to the "clean"
side of the membrane, especially at night when this condition would last for
Would it be better to shut off the flow at the brine (dirty) output of the RO
cartridge rather than the input? If so, are there any valves that would do this
based on the pressure in the storage tank, just like the regular ASO does?
Or am I making a mountain out of a molehill?
Thanks for any info.