Why balling properly is so important

[Aqua-Digital]

How to Select a Calcium and Alkalinity Supplementation Scheme
http://www.advancedaquarist.com/issues/feb2003/chem.htm


from it:

The rise in salinity of these products over time can be very roughly calculated, though there are several reasons why this calculation is only an estimate. For every 1000 meq of alkalinity added in this fashion (and the matching amount of calcium) these products will deliver on the order of 60 grams of other ions to the tank. In a tank with a low calcification demand (defined later to be 18.3 thousand meq of alkalinity per year in a 100 gallon tank (50 meq/day)) this effect will raise the salinity by 3 ppt per year (compared to a normal salinity of S ~35). In a high demand tank (defined later to be 219 thousand meq of alkalinity per year in a 100 gallon tank (600 meq/day)), the salinity will rise by 35 ppt in a year, or approximately doubling the salinity. Consequently, the salinity should be monitored closely in using these types of additives, especially in a tank with high calcification rates.

again exactly right with two part, where as true balling the rise is not out of balance and easily adjusted by water changes, where as the rise in salinity in 2 part leaves an out of balance system,

[Aqua-Digital]

Nobody is stating true balling does not raise salinity of course it does, however it raises it no different to adding new "REEF" salt to your tank. where as 2 part raises it by only adding the sodium chloride to your system, or as stated above some unknown amount of missing or apparent elements.

Most 2 parts use bicarb and calcium from sources never designed to go near a fish tank, no way were these balanced with corals needs in mind.

Thats the difference.

2 and 3 part are not completely the wrong way to do it, thats not true, however they are just missing the final ingredient to do it in a way that stops any fall off in balanced trace elements.