I have started adding bleach directly to my vinyl pool about 1.5 years ago. 2 disastrous pool openings by the pool guys has resulted in me fighting mustard algae for a long time shocking often. The blue prints (I assume it is paint), in the bottom of my pool has faded and even disappeared in some cases. Additionally I now have iron stains galore.
Moving to the add bleach to skimmer point of view now, but I fear the damage has been done.
Btw. the pool has 4 or 5 return jets so the jets themselves don't have a very strong flow. Don't know if that had an impact.