A good idea to go conservative until you see how things react. When a limiting factor (alkalinity , or low P or low N etc) is removed/fixed things can change quickly and in unexpected ways. Some newer research indicates that a little N in the pond fertilizer mix can help but you don't want a lot in most cases. Standard suggestion is 0-46-0 (0-45-0) while most fish pond fertilizer (water soluble)has some N but in low %.