[Myka]

The Prime will detoxify ammonia. Read the label for cautionary advice and dose more. The API is actually my preferred test kit because it is a salicylate kit which only tests toxic ammonia and is compatible with ammonia detoxifiers. How old is the kit?

That is A LOT of food to be adding to the tank! Personally, I'm not a fan of liquid foods unless they are from nutrient lowering systems (like Zeovit, Fauna Marin, etc). You could try dropping the liquid foods (Zooplex, Microvert), and see if you notice any changes in the tank. I think you would only see positive changes. These foods are probably the major contributor to the elevated phosphate - 1 ppm is A LOT of phosphate. Would help to lower nitrate as well.

Coral Excel is a decent product, though I think it is possible to achieve the same results without using it.

What are your SPS colors like? Brightly colored throughout, brown with colored tips, generally rich colors, generally pastel colors...?