So I did my first drain/clean/fill yesterday. I ran spa purge, flushed all the lines, cleaned with a 50/50 vinegar and water solution, added water (well water) through the filter intake with a hose filter on it, dumped a bottle of metal gon in it, replaced the filter and went to bed since it was super late by the time I finished. 

Woke up this morning to this. So I rinsed the filter which was already reddish brown, adjusted the Alkalinity and ph, chlorinated, shocked and not sure where to go from here. 

Forgive my ignorance since this is my first time, but after shocking my chlorine went back down to 1 after being at 4, not sure if that is normal and if I should just add chlorine again. 

Before I do anything I wanted to ask whats next. I have a clorox water clarifier and a scale, metal, stain control left over from the previous homeowner. I still need to add calcium but I dont want to do anything until I know how to proceed. If anyone can provide guidance, it would be much appreciated. 

Also to clarify, I used well water instead of the softened water since the previous homeowner said they had nothing but trouble trying to maintain water chemistry with the softened water, and using unsoftened with a hose filter was much easier. 

New water discolored 12 hours later