EI ferts dosing advice for hard water high in nitrates and phosphates

guynewman

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I have been using EI macro ferts that include MgSO4, KNO3 and KH2PO4 dry salts. I am considering switching to use just KCl and MgSO4 instead because of the high levels of nitrates and phosphates in my tap water. I want to know if that's a bad idea, and if so, why. I know the precept of EI ferts is to provide an abundance of nutrients to ensure no deficiencies, but my tap water IS abundant in nitrates and phosphates.

For context:
I live in an area with tap water that has 31 - 43 mgNO3/l, 1 - 3 mgPO4/l, 280 mgCaCO3/l and 7-7.6 pH.
 

ian_m

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Changing your dosing to reflect your guaranteed to be different test results is quickest way to miss fertilise your plants and turn them to algae.

EI was invented so your don't need to rely on unreliable test results.

Just dose full EI and do not invent your own flawed dosing scheme. Change 50% water weekly, job done no chance of plants running out of ferts.
 

guynewman

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Just to clarify, all the figures for my tap water are from the water supplier for 2018 except the PO4 which was done using a Salifert test kit.
 

ian_m

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Just to clarify, all the figures for my tap water are from the water supplier for 2018 except the PO4 which was done using a Salifert test kit.
Doesn't matter, an unreliable test kit and old water company test from 2018 from their test point on a particular day, not your tap water today. Just dose full EI, no guess work, no getting it wrong. Job done. Virtually all of the people here that change their dosing, because of flawed information on their water contents end up having plant issues, eventually.
 

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