The first thing that I recommend our customers do is adjust for TA (total alkalinity) and calcium hardness. After that I like to leave the balance alone for a few days except for sanitizer.
I'm not a real fan of the MPS strips because it will fluctuate so much you will never keep up with that. MPS is a shock that burns off the organic waste that is killed by the sanitizer.
What you need to test on a consistent basis is the Chlorine content, the PH and the alkalinity.
There are also some performance enhancers like stain and scale, enzyme and other clarifiers that make the water nice and aid in the life of the water in the tub and the spa itself but they are truly secondary to the other three things I mentioned.
I use clarifier as I need it, enzyme every other week and either protect plus or stain and scale the opposite weeks.
Clarifier will coagulate the small particles in the water and help catch them in the filter.
Stain 'n Scale and/or Protect plus will suspend the metal particles in a solution and help prevent the brown line at water level in addition to prolonging the life of metal parts in contact with the water.
Enzyme is a great product that breaks down oils from your body and lotions so that the filter can work more effective.
I’ve just found a new product called “Silken” that you add at fill to make the water feel softer and help with dry skin…I’m going to try it on next fill before I push it on my customers but I let you know how it works.