Reverse Osmosis without a pressure tank?
You can run the reverse osmosis output into a non-pressurized tank with gravity feed to the greenhouse or garden. You would need a float switch to turn off the RO unit when the tank is full.
Some models of RO units don't actually turn off unless either the water inlet is shut off or the back pressure at the outlet builds up sufficiently (via a pressure tank), in which case you would need an electrically powered inlet valve as well as a float switch. Or let the RO unit run 24/7 and provide an overflow pipe from the storage tank to the garden or to a drain.
With a nonpressurized storage tank, (possibly germ laden) makeup air from the room or basement or outside is needed to occupy the tank when water is being drawn. The water would be non-potable unless chemical treatment was done later.
For those eavesdropping for whom gravity feed doesn't work, any number of additional and/or larger pressure tanks can be installed as needed.
The disadvantages of crab apple trees. In summer, the apples are too sour to pick and eat. In winter the birds come and leave dropping all over the place.
Last edited by AllanJ; 09-20-2012 at 09:03 AM.