It's All About The Nutrients... Following a good nutrient regime and keeping it simple will go a long way to ensure adequate uptake of all the essential nutrients. It is advisable not to use too many formulations, as it may be very difficult to trace the exact cause of the problem if there are many additives and supplements in the nutrient mix.

Plants need to have fresh nutrients
available for healthy growth. Ensuring regular reservoir changes
every week is essential. pH and
electro conductivity should be checked while mixing the nutrient
solution. While the electro conductivity reading will help determine
the amount of dissolved nutrients, the pH reading will help in
maintaining pH values at levels that will enable plants to absorb
the nutrients.
Leaching or rinsing should be carried out one week prior to harvest.
This can be done using regular tap water through the system to wash
out excess salts that remain in the growing medium.
Keeping a gardening journal will help in avoiding mistakes and
establish pointers to the right course of action. Making journal
entries regularly will, in the course of time, help build up a
veritable treasure trove of valuable information on various aspects
of nutrients, pH, EC etc.