Thanks for the compliments all.
Epond -
The drip plate has 120 holes (12 rows @ 10 per row). The holes started at 1/8" diameter...now 20 holes have been drilled to 3/16. I'm finding that I am outpumping the drip plate, or at least the drip plate's ability to flow. Over a period of about 4 days, my water level on the drip plate rises by 1/2".
After some testing, I have come to the conclusion that the drip plate seals so tightly that I'm getting a slight positive pressure in the media chamber under the drip plate, which is causing the water to build up. When the pumps are running, my water level in the media chamber is lower than the water level in the pump chamber. When the pumps are shut off, bubbles start to come up from the drip plate. I'm working on a solution.
On the positive side, I have lots of nitrite in the tank, and ammonia is reading zero after 24 hours. Hoping to be fully cycled in 10 days or so.