There are many side reactions that will take place owing mostly to the agressiveness of the O-Cl moiety.
From the wiki (my annotations in braces [ ] ):
Calcium hypochlorite reacts with
carbon dioxide to form
calcium carbonate and release
dichlorine monoxide:
[This reaction will occur]
Ca(ClO)2 + CO2 → CaCO3 + Cl2O↑
A calcium hypochlorite solution is
basic. This basicity is due to the
hydrolysis performed by the
hypochlorite ion, as
hypochlorous acid is
weak, but
calcium hydroxide is a strong base. As a result, the hypochlorite ion is a strong
conjugate base, and the calcium ion is a weak conjugate acid:
ClO- + H2O → HClO + OH−
Similarly, calcium hypochlorite reacts with
hydrochloric acid to form
calcium chloride,
water and
chlorine:
Ca(OCl)2 + 4 HCl → CaCl2 + 2 H2O + 2Cl2
[This is essentially the reverse process for how the hypochlorites are produced, which is an equilibrium reaction:
Cl2 + H2O ⇌ HClO + HCl
Cl2 + 4 OH− ⇌ 2 ClO− + 2 H2O +2e
Cl2 + 2 e− ⇌ 2 Cl− ]
End Wiki quote-----------
The answer is essentially that all of this crap will be around.
The primary interplay here is as follows:
The hypochlorite salt will not be entirely soluble. So you have an equilibrium dependency there, it will prefer harder water to go into solution. Once dissolved, there is a second equilibrium that is established relative to the pH of the solution.
At 7.53 pH (pKa of hypochlorous acid) there will be 50% ClO and 50% HClO in the solution.
Now, both species are very reactive along their own pathways--and depending on what else is around that they can scavenge the equilibrium will be pushed in one direction or the other. So if the HClO is able to perform more side reactions the end result is that the equilibrium will favor that side and vice versa.
The resulting species will then go on to affect pH. When you're done you end up with a chemical soup of chlorinated species depending on exactly where you started and what was in your water in the first place.
It should be getting clearer and clearer why this stuff is bad for microorganisms and molecules that stain. It literally rips them apart via oxidative and reductive processes.