Sorry I'm late with a reply to this post. I have grown using the Dutch bucket system and GpsFrontier was absolutely correct with his reply. Run the 1/2 feed pipe level with the tops of the buckets then run feed lines directly to the plants. The return piping should be located very slightly below the buckets on an angle towards the reservoir. Also why do you feel the need to run the
pump constantly or even for 30minutes? If you're using the system in your home no need to run the pump that long. If you are growing outdoors here's what I did.
On a hot summer day I would only run for 8 minutes on 20+ minutes off. If it was a really brutal day of 90 degrees + with 80% humidity it would turn on around every 12 minutes. On cooler days in low 80's or upper 70's I would run 5 minutes on 30 minutes off. You can play around with it and see what works good for you by observing the plants and make sure they look good. If they look like they need more water just adjust more time for watering. Keep a log book on what cycle you're using and the temperatures for each day. You will eventually see a pattern that you can adjust when the temperature changes.
If growing indoors you should still keep a log book of the cycles you're using and adjust it till you find what the plants look happier with.