PO4 is way too high. It needs to be lowered. I'm surprised your adult fish can survive in that. Get yourself some GFO pads for your filter box or throw some Cheato in your sump to eat that up.
On baby clownfish: They will be lost. You can expect about half to die within the first 2 weeks, before they even start metamorphosis. That's when they get body color and start getting their stripe patterns. After that, you'll lose half of what's left in the next few months. When I was hatching Ocellaris, I'd get anywhere from 90-150 survivors after 6 months out of about 400 eggs.