Dry Fert confusion???

utahfish

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In the past i've used k2S04 to supplement potassium calcium chloride for calcium and magnesium sulfate for magnesium.
Recently ive discovered potassium chloride commonly used in home water softeners is cheaper than potassium sulfate.
Question is. If adding Kcl potassium chloride softens water than wont it in turn cancel out the added magnesium and calcium??? Plants need magnesium and calcium as well so would sticking with K2So4 over Kcl be more effective at growing plants or does it not matter. Im confused???
 

essjay

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I have not come across potassium chloride in water softeners, only sodium chloride; but that does not mean that potassium chloride isn't used.
Potassium chloride (or sodium chloride) is used in an ion exchange resin in these water softeners. As water passes through the resin, the calcium and magnesium in the water are taken out and replaced by potassium/sodium.
It doesn't matter whether you add potassium sulphate or potassium chloride; it's the potassium that is the important bit, the chloride and sulphate don't matter.
But the water softener is already adding potassium to the water (assuming it uses potassium chloride not sodium chloride)


However, natural sources of fresh water contain little potassium or sodium. Fish have not evolved to cope with them. Using water that has been through this type of water softener in a fish tank is not good for fish. There should be a bypass tap somewhere, and this should be used for fish tanks. If this water is too hard for the fish in the tank, RO or some other type of pure water should be used to dilute the hard bypass tap water.
 
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utahfish

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Thanks for the reply, im not wanting the potassium chloride to soften the water i just need it for the potassium. In the past ive used K2so4 (,potassium sulfate)to get my plants potassium but ive found that potassium chloride is cheaper and more readily available but im worried that the potassium chloride will remove the added magnesium sulfate and calcium chloride i add for the plants?
 

essjay

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Sorry I misunderstood - I thought you meant you had a water softener and had recently discovered what was in it.


No, adding potassium chloride as a fertiliser will not affect calcium or magnesium. In water softeners, it is the resin that removes the calcium and magnesium not the potassium chloride. The resin swaps calcium and magnesium with potassium. Since the resin will be nowhere near your tank, adding potassium chloride cannot affect the calcium and magnesium in the tank.
 
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utahfish

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thankyou, you have been very helpful!
 
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