Ro System questions
 

I want to get a RO system in my Gh. Do I need to also get a pressure tank? The Gh is 12' high so I need to be able to water 9'. I use about 50 gals when I water. How should I set it up

Unless you invest in a very large system - 750 gpd, for example - RO systems are not "on demand" water supplies, so you do need some storage and delivery capability.

A pressure (bladder) tank capable of delivering 50 gallons at a session is expensive. For example, a 90-gallon tank (water capacity about 60-65 gallons) retails for about $1000.

Instead, what most folks do is connect their system to an open-air tank via a float valve, then use a pump to propel the water for delivery.

When I first got an RO system (before I started building and selling them), I used two 55-gallon plastic drums I got for free from my local car wash. I put one (with the float valve) above the other on a 4x4 stand I built, and put a spigot near the bottom.. I mixed my fertilizer in the lower one, and used a hefty submersible pump to push the water through a hose. The upper one was automatically refilled by the RO system, and when the lower one was empty, I just opened the spigot and refilled it.

Now, I have a shallow-well pump with its own smaller bladder tank to propel the water from the storage tank, and the fertilizer is added via a metering pump in the piping.

I have a lot of RO info HERE.

I use an open air tank for my watering/nutrient solution. It is filled from my RO system using a float valve shutoff. A pump is used to send pressurized water to my spray wand. I use this same open tank when applying pesticides & fungicides. I still also use a small bladder tank with the RO system. It provides me with on demand RO and also connects to the open tank float valve.