Will MPS (spa shock) Raise TA?

[Gary]

Anyone know?

[HotTubMan]

NO. It will lower TA and pH.

[Gary]

That is what I thought, the potassium could raise but the peroxy would lower it. So depending on the mix it might lower or raise it.

[wmccall]

NO. It will lower TA and pH.

That is my experience as well. Perhaps more so the PH than Alk.  My water is normally low in both, so I notice it pretty quick.  I shock with MPS every 1-2 weeks and after 2 shocks I frequently have to raise the PH.

[HotTubMan]

True MPS will behave as discussed above. There are several variations of this compound.

One such example is potassium persulfate. This compound has an alkaline nature. This the active ingredient in a Beachcomber product called Care Free. The other ingredient is sodium bisulfate (granular pH minus).