Yes, do not limit your nutrients. However, lets say you have a low light tank, decent bioload, no CO2, few plants. Do you need EI? Most probably not. I wouldn't dose EI for that setup. The waste from fish will be enough to supply the plants. In fact, i would think that EI would just build nutrients over time to a very toxic level since they arent being consumed and even teh 50% WC wont reset the tank enough such that the buildup is being managed.