like frmrboi said you can't. the whole purpose of a flush is to give your plant pure water to get all the chemicals out of it before harvest. you can't flush with more nutes cuz that would kind of defeat the purpose.
You can flush your plant with a flushing solutions like Clorex but that is ab out it. Clorex for 1 or 2 water cycles then just water. Flushing removes built up salts in the medium and also takes the nutes out of the plant for a clean product.
You can flush your plant with a flushing solutions like Clorex but that is ab out it. Clorex for 1 or 2 water cycles then just water. Flushing removes built up salts in the medium and also takes the nutes out of the plant for a clean product.