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Old 09-21-17, 09:47 AM   #839
jeff5may
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Another good supplement to consider adding to your water is magnesium sulfate, aka Epsom salt. The Solanaceae family of plants you are growing (tomatoes and peppers) are gluttons of calcium and magnesium. Both hydrated lime and Epsom salt act to buffer the water around a pH of 6.5 or so, which helps avoid nutrient lockout issue. Definitely keep the pH below 6.9 to stave off all kinds of nasty side effects.

As a general rule, when you add lime, you also want to add a little gypsum (calcium sulfate aka plaster of paris) with the lime. If you're using dolomitic lime, it already has some magnesium in it, so the Epsom salt isn't so necessary. But if you're adding calcitic lime, it has no magnesium in it, and adding Epsom salt will get your available magnesium balanced.

The reason I point this out is because next to npk, the next 3 most important elements to watch are sulfur, calcium and magnesium. In aquaponic systems, nearly all of the trace elements are taken care of by the fish poop.

Last edited by jeff5may; 09-21-17 at 12:56 PM..
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