For a long time we did not want holes that would leak so we went to a boat shop a got a small hand bilge pump for 20 something. We put a hole in the top between plants just big enough to slide the pump in and a 5 gallon bucket to catch the water. The hardest part is moving water.

Now we have a small pump from slowes that you can hook up water hoses to. Throw a short hose in the rez with a filter on the end so you don't pick up any looose hydrotron. Did that and burned up a pump. the other end is a 100 foot hose that waters the flowers and they do look very happy.