Unfortunately Miami Reef won't be here for my most recent observations regarding urea/ammonia (

) but the project continues:
I temporarily stopped dosing any nitrogen containing solution per Miami's recommendations as my nitrates were reading between 15-20. Over the course of around a week, things started looking pretty poopy. My toadstool and grubes gorg were extremely ticked. I noticed many corals expelling zooxanthellae at peak light level/mid day, as well. Nitrates began to trend down after stopping all dosing. Because things were looking so unhappy, I decided to put some ammonium bicarbonate back on, sans urea, at a much lower rate than I originally was using (6mL per day, I was up to 27/day previously.).
Things are coming around...the grubes and toadstool are coming back out, but nitrates are continuing to trend down (currently at 5ppm.) I'm going to try an ammonium and urea combo again, but at a lower urea level. I'm actually thinking as low as 1g/L urea to start.
One other observation to add: I mentioned previously that I had severe blinding over of my filter socks (mesh, not felt) when I started the ammonia dosing. This has continued to be the case - it ceased when I temporarily stopped, and recurred after starting the ammonia.