How many fish do you have in your tank?
Feeding once a day is pretty high imo
. Fish are fine being fed every 2-3 days, some can go a week without being fed by us.
Keep in mind everytime you put food in the tank, it stays in the tank until YOU take it out. The protein skimmer helps with that, but doesnt get everything out. Also, with your CuC, the food will still be in there, just in another form (waste).
It's a good idea with every water change that you siphon out some of the detrius from the rock and sand to remove some of the left over fish poo and food. That will help prevent further spikes and helps keep phosphates in check.