New poster, taking care of new vinyl liner

[jollyreaper]

South Florida, in-ground vinyl pool, 7000 gallons.

We'd managed to bleach the liner pretty good and solid thanks to following pool store advice on maintenance. Based on my reading here, it sounds like we had too much chlorine.

There aren't many vinyl pools in South Florida and the tech who installed it gave a lot of advice that was contrary to the pool store advice. I've tried vetting what he said online and gotten even more confused. Hopefully, this forum will help me dispel some of the confusion.

According to the tech who did the liner, he said all we need to do is put in the powdered stabilizer, cyanuric acid hydrate, 1lb through the skimmer each month, then add a little less than a half jug of liquid chlorine weekly, also through the skimmer. Use soda bicarbinate to increase the ph as needed. The surprising thing he said was to NOT use muriatic acid, calcium hardness, and absolutely no floater chlorine tablets as that is acidic and ruinous to the liner.

Ok, upon reviewing commentary I see confirmation for the the calcium hardness since that is more of an issue with cement pools. The liner is inert and therefore doesn't present an issue. The pool store still argues with this but the tech says that their machines are all assuming concrete pools as standard.

I have not seen any confirmation for the muriatic acid comment which is a bit of a concern because we've had a pretty heavy rain that's raised the ph.

So, what is the best way of lowering ph in a vinyl pool?

Here are the current numbers:
Total Alkalinity: 160
ph: 7.8
chlorine: not present, supposedly only needed once a week, we are adding on schedule but it won't last

Our test kit says the ideal ph range is between 7.4 and 7.6 and we need to add acid now. The liner guide says 7.2 to 7.6. The trouble free pool guide linked to from here says 7.8 is good.

So, what's the real answer?