MB,

Here is how I would look at this problem.

1. What is the water demand per day or week for your plants at maturity? My general estimate is about 1.0 gal per plant per week. If very arid climate say1.5 gal per week for 200 plants is 300 gal per week. That is equivalent to one of your tanks which is good storage capacity. Do you produce 300 gal per week in rainfall?

2. You need to find out the flow and pressure of your 1.5 HP pump. The outlet size does not matter at this point. The smaller the pipe size the more velocity in the pipe. Velocity is only harmful when it exceeds 5 fps and can cause water hammer(blowouts). You can look up a 1.5 hp pump that is similar to yours on Google and see what the pressure is. The pressure is important because you are using it directly for drip.

3. Size a pump that would put out 150 gals for 25 mins. That would be a 6-10 gpm pump with 10-15 psi operating pressure. I bet your pool pump would be a lot more than that. You probably would need a pressure reducer on you pool pump. and gate valve to restrict flow.

4. Let us know what you find out or have more questions.

5. Aloha