I think I remeber this topic coming up here once before and i wanted to
ask for some advice. I am getting ready to swtich from tap water to
reverse osmosis water for my greenhouse. Right now I run the tap water
through a dosamatic and use a diliuted fertilizer on every watering. My
current water demand is about 5 gallons per minute for 5 to 10 mintues.
I plan on using a 300 gallon water tank that will store up to 150
gallons of RO water and have room for up to 150 gallons of rain water.
I am trying to work out how I am going to pump the water to the
greenhouse though. I need about 5 gpm but would like to have about
10gpm since I plan on doubling the size of the greenhouse this year. I
would like a system that kicks on with a pressure switch rather than a
simple sump pump that I have to plug in each time. I was looking at
some setups at lowes that involve a 1/2hp pump and a pressure tank of up
to 42 gallons. I dont think I need a pressure tank that big but thats
what the guy there suggested.
I also saw that Harbor Freight has a 3/4 hp setup with a 5 gallon tank
for $80, thats about 4 or 5 times less than the setup from lowes. I
know that harbor freight normally sells junk, anyone have any experience
with this setup?

I would appreciate anyones advice.

Thanks
Dustin