@MSmiley, this may seem overwhelming, but I can assure you we can keep it simple. Let me highlight some basics to help:
1 - With an indoor pool, you only need about 20-30 ppm of CYA. Then maintain the corresponding FC level to match that CYA as noted on the
FC/CYA Levels. That's all you need to worry about for the algae prevention/sanitation portion of your water.
2 - To keep the water comfortable to the skin & eyes, prevent scale and reduce the likelihood of staining, we balance the TA, pH, and CH. The CH technically isn't needed since our FG shells do not contain plaster, but the CH can help to buffer the effects of staining. TFP recommends a CH of 200 only because we don't know if some FG owners have a waterline tile (plaster) or heater requirements. IMO, if none of those issues apply, a CH anywhere between 100 - 300 is fine. PH & TA will always be your most important and easily adjustable items in this area. PH is good anywhere between 7.2-7.8. For most of us, PH tends to drift up to 7.8 or higher, so we have to use muriatic acid to lower it a bit. If the TA is over 80, it can enhance the PH's ability to climb faster. If your TA is anywhere between 50-80 it's fine. "Generic" industry TA levels say 80-120, but that's because they expect the owner to use acidic tablets. TFP does not.
Once you receive a proper test kit, you will have 100% visibility of the water chemistry. Not hard at all. We'll be here to help coach you along the way.
As far as those darker blotches are concerned, I would be suspicious of the application versus anything chemically you have done to this point. Not sure if I missed it above, but have you reached out to the contractor who did the new finish? Since you have been following their recommendations (and Ecofinish) to this point, they should be taking good care of you for the first season.
Let us know if you have any other questions. Stay cool!