You're right. NH3/NH4 = Ammonia.
Actually, ammonia / ammonium. Non-ionized / ionized. Terrible / bad. But I got what you meant.
You're right. NH3/NH4 = Ammonia.
I hope this works out for you, Greg, but I fear that PO4 levels of 0.5 ppm are going to fuel a serious algal bloom. Hopefully, you can keep on top of it, and try to lower the PO4 levels with some water changes using RO/DI water to mix with your salt.
Not only that, but studies have shown that phosphate concentrations above .02 ppm drastically reduce calcification in corals.