I have a couple of RO units running. Firstly, I would not mix it with tapwater because you will just be contaminating your excellent RO water, Instead, get some KENT RO right or I think theres one called electro right. add this and this will remineralise and buffer up the RO waters PH. As far as I know, you cant get a hose adapter for them. You are right when you say that the membrane has to stay wet once it has been used. the best way to install them is to put a saddle valve onto your copper pipe under the sink. run the pipe through the RO and then into a five gallon prewing bucket or camping bucket. I have an RO storage tank with float switch but all the people I know have found that the best way to do it is to place the buckes in the bath etc and open the saddle valve. you may need a valve on the exit (s) to turn the RO off as well. If you just want to run it for a day a week etc, then get a valve for the water out pipe and turn this off and this will make sure that the membrane stays wet. if you run it continuesly, there is no need for another valve. i would not get a bare bones type of RO. although they may be cheaper, they are more expensive in the long run. if you get a 3 pod one which has a pre filter carbon and membrane, then it will last longer.
up to now, I havn't had any problems appart from when I forget to empty the strage tank and it floods. mines in thre fish house so it dosn't really matter if it floods, but thats why most peiople run theres into a bucket in the bath.
