From what I read the remaing 10% is salts

Is that a yes or no? Bought it from Culligan water.

Shouldn't be an issue just double check the salt it could be high in some stuff and low in others but then again the dosage would be low enough not to have An adverse effect anyway it also says nothing about aquarium use but then again we in the hobby have a habit of using stuff not designed for aquarium use :twised:

i have been using calcium chloride ice melt since january with no adverse effects and at $40 for 50 lbs you cant beat the price. buying in bulk in this hobby leaves more money to buy frags and other gear.

3 years for me with same stuff.

Ive been using pottasium salt from a bag of water softer (says its pure and "healthy to drink") without problems. It is food grade at least, the bag states "pure pottasium Chloride". Bought it at Lowes

I'm holding a bottle of lab grade KCl in front of me that I just used to do a series of nitrate and ammonium extractions on a batch of soil samples for my masters. Since it's lab grade, it also lists it's impurities:

Iodide: 0.002%
Bromide: 0.01%
Chlorate and Nitrate (as NO3): 0.003%
Other Nitrogen compounds: 0.001%
Phosphate: 5ppm
Sulphate: 0.001%
Barium: 0.001%
Calcium, Magnesium and R2O3 precipitate: 0.005%
Heavy metals (as Pb): 5ppm
Iron: 3ppm
Sodium: 0.005%

I'm sure there are more pure forms of KCl available for higher level analytical chemistry, but that's what the University of Calgary considers to be 'Lab Grade'. I imagine the list of impurities for KCl that you can buy in the store or in bulk would either look similar, or be slightly to much worse. The chances that your'e going to get a KCl additive (or any kind of additive for that matter) that only adds KCl are pretty much zero. Not sure if any of those listed parameters would be enough to cause problems in a tank though, or which contaminants are likely to increase in concentration when you go with a lower grade salt.