Phosphate is essential for life. It is a component for DNA, RNA & ATP & also the phospholipids that form all cells membrane. So, foods will contain this to ensute your fishes stays healthy. I rem when i juz started keeping fish, somebody told me, do not overfeed your fishes. Meaning to ensure all food thrown into the tank will be eaten up, reduce too much nutrient bulit up in terms of NO3 (due to food decomposing) & release of PO4 from the food to the water. That is also why we need to run PO4 removal media, to constantly remove the PO4 introduce into the water thro' uneaten food & fishes poo. So, no need to be alarm with the presence of PO4. Feed sparingly.