Hello and Welcome to the forum!Wipe your feet at the door and stay a while.
Let me help as much as I can.

1.I have NEVER,EVER heard of sand eating chlorine......EVER,EVER.
2.Don't buy OR add anything else from a poolstore...load up on Liquid chlorine or bleach
3.Get a GOOD test kit....Taylor k2006 or 2006c are favs here(actually should have been point 1 on list!)
4.With CYA of 86 you must shock pool to 20ppm and KEEP IT THERE by testing pool 3 times a day and adding chlorine as needed to maintain 20ppm.You must add about 7 gallons of 6% bleach AT ONE TIME to pool to get to 20 ppm for your size pool.
5.Run filter 24/7 til it clears up...it will turn a blueish haze as it kills the algae
6.With CYA of 86 you MUST maintain Free Chlorine between 5-10 ppm AT ALL TIMES after that or risk algae

Alkalinity is high,you'll want to knock that down(dont know exactly what number as I am actually sleeping while typing this,somebody will be here to help soon though)


The problem is you are not maintaining a high enough chlorine residual for your cya.They are connected .That's were the algae comes into play.Do NOT add a stabilized chlorine(pucks..either tri chlor or di chlor) as this will add MORE cya to the water!
Check out the pool calculator in the forum it is a magnificent tool.Read the BBB stickies in forum also to better aquaint yourself.