Is it okay to feed at the recommended EC if I only feed once a day?

Gauge plant responses, ensure 20-25% runoff and keep an eye on the runoff ph, since you will have less control over drybacks when hand watering. Raise the EC if the runoff pH is drifting more than .5 upwards or you notice deficiencies/light green growth. Decrease EC if the pH runoff is dropping more than .5 of the input and/or you see tip burn.