Your res will tell you. If your EC is 1.18 and dropping daily, then yes, feed more. If it's 1.18 and rising, then you are feeding too much and need to lower your EC.
When your EC remains constant (or close to) day after day you will know that you are feeding at appropriate levels.
Large fluctuations in heat, RH, or pH could affect this so hopefully your indoor environment is pretty stable.