All non stabilized form of chlorine (liquid sodium hypochlorite and bleach, cal hypo, and lithium hypochlorite) are alkaline but the reaction of the clorine in the water when it breaks down in disinficting is mildly acidic so the net effect is fairly pH neutral. Stabilized chlorine (trichlor and dichlor) are both acidic, especially trichlor, and still have the acidic reaction when the clorine in the water breaks down so they will have tne net effect of lowering pH and TA.
MPS (non chlorine shock) is also acidic and will add sulfates to the water. MPS has no advantages in an outdoor pool, IMHO, but is useful in an indoor pool since it works differently than shocking with chlorine. It does not destroy chlorramines once they have formed but can help prevent them from forming if MPS is used on a regular basis. In an outdoor pool the combination of high chlorine levels from shocking and the UV from sunlight efficiently break down chloramines.
Bottom line is this. If you are using a stabilized chlorine or MPS you want to run your TA at the higher end of the range (100-120 ppm) to combat the acidic product. If you are using an unstabilized chlorine (or have a SWG) you should run your TA at the low end (80-90 or even lower than that possibly) to obtain a more stable pH and have less acid demand. Also running your pH at 7.8 instead of lower will help reduce acid demand with unstabilized chlorine. I am not going to get into all the technical details here since the chemistry does get involved but these techniques do work.
