Need on-demand rainwater 150' from 2500 gal tank

Howdy from Central Texas!

I have a 2500 gallon poly tank collecting rainwater from my roof at the South end of my house.  My garden is 150' away on the North end of the house.  I've been using gravity feed through
a garden hose, which is very slow as the elevations are similar and relying on the full tank for pressure.

I just purchased another 2500 gallon poly tank that I want to use as an overflow because we get enough rain to easily fill both 2500 gallon tanks.  

What are my best options to get on demand rainwater to my garden 150' away?  The elevations are approximately equal.

Thanks!!!
Mark in Cedar Park

I have a 12v DC (AC version also available) transfer pump from Harbor Freight that I really like and it was relatively affordable. You can connect your garden hose, or drip line, etc. with a couple simple fittings from a hardware store, and there's good pressure/flow rate.

Thanks Jonah!

Can you provide more info on your setup?  Which pump make/model?  I'm thinking I might want to add solar at some point as well.

A gravity feed can work very well. And, there is very little to go wrong. However, the pressure is low. So, to increase flow, the diameter of the pipe must be increased.

Or do it like me, I'm cheap, so I use skinny pipe/hose and flow it into a stock tank in the garden for watering. A float valve keeps the stock tank from overflowing. I find that I can move a lot of water by hand, way faster than a garden hose, as long as it's central to the garden. (I put a little raft or a long pole in the stock tank, so birds and bees can get a drink without drowning.)

I use a 2 inch polyhose across the land and move 20,000 Gals about 200ft regularly.
In you case if you have 24 hrs etc I would try 1 inch polypipe.

it sounds like with about zero elevation change gravity would mostly work but as the tank level dropped the pressure would as well and it would take longer and longer for the same amount of water to come out of the tank, making consistent watering of a garden tricky.  Our setup is  (3 x 2500gal.) that are filled from the roof of a steel building.  Our garden is actually about 8' higher in elevation and about 75' away so gravity feed wasn't an option.  We landed on a Harbor Freight shallow well pump that is connected to 3 "yard hydrants" spread throughout our garden.  The pump cost $140 on sale and has a 2 gallon pressurized accumulator tank attached.  It brings the line up to 55 psi and shuts down until the pressure drops below 35 psi then it will restart and bring the pressure back to 55 psi, etc.  These are built to run an entire small house so the cycling they do is expected.  I've ran our gasoline powered pressure washer for 3 hours via that system and it worked great.  For irrigation you could add a garden hose timer to the hydrant and then drip tubing or sprinklers in the garden, similar to what we do.  This has been in place for 6 months now and it's been perfect.

I have used a lot of Teel pumps in industrial applications. Very reliable & depending on which one used ... a lot of flow & pressure.

https://www.grainger.com/search/pumps/centrifugal-pumps/compact-submersible-centrifugal-pumps?sst=4&ts_optout=true&searchQuery=teel+pump&categoryIndex=7

If you used one of those industrial style pumps you'd have to include a pressure switch somewhere unless you want to control the pump with an actual switch every time you needed water.  The shallow well pump style includes a pressure switch so you get actual "on demand" water without having to do anything but turn on a faucet (or hydrant, or hose bib or whatever you have it connected to).