Selenium is usually given in general mixes as Sodium Selenite the inorganic form. This may be sufficient for the daily requirement in areas with good levels of selenium in the soil but problems can occur with poor absorption due to competition with other minerals. The liquid form of Selenium is potentially extremely toxic if too much is given, the dose rate is very small and therefore can be easily overdosed, or since it is often not a daily dose, it can also be forgotten.