So I discovered a trick last night – if I run my finger over a clownfish nest, the fish inside the eggs will wiggle if alive. So despite having had no appreciable hatch all day, I pulled the tile, sanitized it again with H2O2, and threw it back in the larval tank.  I DID get a few eggs to hatch during the vigorous aeration in the sanitizing dip, so that further told me I was on the right path.
I didn’t get to check the nest until 4 PM today, but sure enough, there were significantly more larvae in the tank.  It required a new strong feeding with rotifers.  I once again tested the eggs…still viable, so I put some ChloramX in the water, and left the tile back in there.  They may not get checked again until tomorrow…