Well I've never heard them called Ro
reactors but a good place for Ro
systems is bulk reef supply. Don't have one but from posts on here they are good.
What size tank will determine the size you need. They are rated in gpd ( gallons per day). Usually 75 100 and 150 gpd.
They will be set up where your water source is. Either a sink or spicket. I got mine with a hose adapter and bought a y valve an have it hooked up to the cold water supply for my washing machine. You can make then "portable" where you just unhook it and put it away when done.
Additional things would be a tds
(total disolved solids) meter. You can get handheld units or ones that go on the water lines of your unit. This shows you how dirty the water is and should be 0 on the purified water.
Also some people get pressure gauges to monitor, this can tell you when the filters are getting clogged.
If you house has low water pressure you may need a booster pump as well.
The only other thing would be bins to store the water. I use 35 gallon rubber maid trash cans.