Got a call back from Lindsey -
Recognition that the possibility of cloudy (undissolved) mix could be detrimental to sensitive organisms, tho "in our experience, we have not witnessed any problems". This is fair and, along the lines of what RBU1 is saying. And she added that it would be irresponsible to presume that adding cloudy/un-dissolved mix to a system with particulary sensitive animals could not be potentially bad.
We each need to draw our own conclusions here. if you are comfortable with it - fine, and if not - then don't.
I guess I come back to this: if the salt has not had the opportunity to completely dissolve, how can it possibly be percieved/accepted by corals as chemically compatible with what they have been accustomed to? And what about the lowering of the alk. after mixing, and not using it for a couple of days? ( Reports form users of Tropic Marin Pro have stated the opposite. Low initial alk, but it climbs after mixing for a day or two) Still have some thinking to do about this....
However - if you are doing comparitively small water changes to the overal volume of the system -probably far less chance of any "shocking" of animals.
We also talked about teh impact of the temperature of the water influencing the solubility of the salt.
It seems that ideally if the water temp. is 73-75F, clarity is achieved much faster. But at 78 and above - one gets precipitation....
So - the selection of anhydrous ingredients to make Salinity, which helps to make a product that can fit 225 gal of salt @ 1.026 ....also creates a significant exothermic reaction when mixing it up, if you pour in all of the salt needed to make the batch inteneded - at once ( Thank you Boomer for pointing that out!)
So it seems that what I have learned here is this:
In order to achieve the clarity that I am more comfortable with, (- and more importantly - within the timeframe recommended, so that the alk. does not drop -) I should start with cooler water - or add the salt much more slowly, keeping the temperature rise to a minimum. (Perhaps placing a digital thermometer with remote sensor in the mixing vat...?)
T