# Which dry salts cannot be mixed



## Michael1212 (28 Mar 2021)

My apologies if this topic has been beaten to death so please bear with me.  I'm currently working out my dry fert dosing regime, and to simplify things each day I'd like to pre mix my ingredients into perhaps just three containers, then spoon salts in from there.   I'd like to know:

Which chemicals cannot be mixed together in dry form?
Which chemicals cannot be mixed together in wet form? (should be dosed hours apart)

My raw ingredients list is:


Ca(NO3)2.4H2OCalcium Nitrate TCa(NO3)2Calcium NitrateKH2PO4Mono Potassium PhosphateKsSO4Potassium SulfateMgSO4Magnesium SulfateCaCO3Calcium CarbonateK2CO3Potassium Carbonate

I recall reading that Iron and Phosphate don't play nice together, and that the  Calcium Nitrate can form Calcium Phosphate or Calcium Sulfate?

Greatly appreciate any and all advice.  I plan to ei dose, but  I also need to remineralize my RO water (changing 10 % each night).


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## Oldguy (28 Mar 2021)

Michael1212 said:


> My raw ingredients list is:


I would simplify the list, have either calcium nitrate or calcium nitrate T. You can adjust the quantities either way.

Calcium carbonate is virtually insoluble so delete from list.

Calcium will form a virtually insoluble phosphate and a sparingly soluble sulphate

Iron and phosphates will form a virtually insoluble complex.

Better to use potassium bicarbonate than the carbonate, less effect on pH

Best to have one lot of chemical to re- mineralize  the RO water, one lot for EI macro dosing and one lot for Iron and Trace dosing.

Even simpler use tap water to re-mineralize the RO them follow EI by dosing macros and micros on alternative days. Do a weekly 50% water change.

Tap water analysis can be obtained from the supply company, just look at total hardness to work out ratio of tap to RO. I use rain water and tap water and add magnesium sulphate (UK waters are typically low in Mg salts) and follow EI there after.

Iron and trace elements are best as chelated compounds.

So have a EI mix of potassium nitrate and potassium dihydrogen phosphate, a chelated iron/trace mix and cut the RO with tap water to get the hardness you need. (add Mg salts if these are low in your tap water).

Hope this is of some help. Others on the forum will give you links to threads on this and other forums. ( I'm a paper and pencil guy)


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## Zeus. (28 Mar 2021)

Might be worth a look at the IFC Calculator takes care of all the solubilities in the fert solution and in tank, plus tally's up all the salts you use and the resultant ppms . Once set up and mastered takes care of the whole fert regime which ever you choose to use or Clone a commercial fert


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## Michael1212 (29 Mar 2021)

Thanks Zeus, that calculator looks very useful, I will study it once I get off work.  And thanks for the information Oldguy.  At a high level I'm hearing: don't dose PO4 at the same time as FE or Ca.  I picked up a copy of my water report, and Mg is about 1.4 ppm, although the range they quote on most params is quite wide.  My water change setup is built in, hence the questions.  Also I can't get my hands on Potassium Nitrate here, so I'm stuck using Calcium Nitrate.


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## Zeus. (29 Mar 2021)

Michael1212 said:


> Thanks Zeus, that calculator looks very useful, I will study it once I get off work.



We should be having a update is week with a few minor bug fixes, more salts and commercial ferts to clone and improvements also. nothing major but always nice to be on latest release and @Hanuman has made it a little easier to use also.


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