Citations?
That didn't seem plausible to me so I ran a little experiment to confirm or deny your assumption.
In a 20ml beaker with 15ml of RO water I put 10 drops each of potassium silicate, (Rhino Skin), and REMO CalMag made with calcium and magnesium nitrates. Adjusted pH to 6 and no sign of precipitates.
No precipitates there either. I even added a bit of the Rhino to the Epsom/CalMag mix and nada.
As these things have been used successfully in horticulture and hydro-culture for ages I'm sure problems that you have put forth would have been common knowledge by now.
I searched pretty well and could find no references to either issue so I wonder where you might have come up with the ideas?
totally understand the need for citations.
I can look around for testimonials but here is the balanced chemical reaction for the potassium silicate/calcium nitrate mix:
K2O3Si + Ca(NO3)2 = 2KNO3 + CaSiO3
Potassium Silicate + Calcium Nitrate = Potassium Nitrate + Calcium Metasilicate (also called wollastonite)
Calcium metasilicate (aka calcium silicate) has a solubility in water of .01%, so 99.9% will not dissolve in water....(according to Wikipedia, so thats not a great source but I have seen that figure elsewhere, so maybe take that with a grain of salt)
Not going to lie, I have no idea what the concentrations of each base chemical are in the products you are using and I wont pretend to know the required concentrations of each in order for this reaction to be visible, but it does happen.
From my personal (and thus non provable) experience, it takes a few days in the feed solution to notice precipitate from this reaction. Like I said, I removed this potassium silicate from my feed solution and the precipitation stopped. Correlation does not equal causation of course, and I am no chemist so maybe something else is going on, but this is the best my dumb ass can up with haha.
But your right, I am having a hard time finding others talking about this reaction occurring online... perhaps I was mixing my silica in with my feed at a much higher rate than other products do? For reference I was using Agsil 16H as my silica source.
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As for the reaction between Epsom salts and calcium nitrates that should be readily visible at somewhat higher concentrations. I found out the hard way when I tried to make my own cal mag solution, as soon as I mixed the two high concentration solutions the ensuing mixture turned white and chalky with visible settling after a few minutes. I thought I was being soooo smart, but now I know why its always cal nit and mag nit instead of cal nit and Epsom.
Here is the balanced reaction
MgSO4 + Ca(NO3)2 = CaSO4 + Mg(NO3)2
Magnesium Sulfate + Calcium Nitrate = Calcium Sulfate (gypsum) + Magnesium Nitrate
I was able to find a forum for banana growers talking about this reaction:
http://www.bananas.org/f312/just-figured-out-not-add-calcium-22319.html
Does this make sense? I always end up second guessing my self. I think I balanced those equations right... at least chemical aid.com seems to think so lol. I could be wrong so if im spitting bullshit just let me know