Thank you John! Very nice summary of where to start with EI doses. This has been needed in a concise format for quite some time.
People should realize that there are situations where the above doses may need to be modified. These might include (but are not limitted to) higher than normal levels of nitrates or phosphates in your tap water, a very heavily stocked tank - especially with heavy feedings, or if you routinely go longer than a week between water changes.
The above methods were developed for high-light, CO2 supplemented systems as John mentioned. Low-light or non-CO2 setups are MUCH less likely to become nutrient limited and you can get away with smaller doses and go longer between water changes.
Also, many people feel that a supplemental iron source is sometimes required, depending on the exact composition of your micros.