Would you mind providing a bit more information about your misting setup? I am looking into doing the same for my 18x32' greenhouse. I have city water which is pretty clear so I am going to try this as-is and do a RO system if it turns out to be necessary.
Brian, you should get a TDS meter and check how much junk is in the water.
For your size greenhouse you could probably use the small one like this. Its a CAT .13gpm
To be honest it would take me a LOT of time to tell you everything you need to make it work. Theres a ton of pipe fittings and stuff you will need to source from multiple places. I have it on a humidistat and have a relay setup, its own breaker etc. I ordered the pump from kleen rite in PA which sources it from CAT.
The mist line and misters and mist fittings are from aeromist.com and the pipe fittings are from mcmaster. Relay was off amazon.
Basically you are going to need to know how to do plumbing and electrical to set it up.
I will take photos of it when I put it together later today. Then if you want you can call me to discuss later in the week.