Welcome.
Ben put it succinctly.

BTW, No matter HOW nice the pool store is, I will bet dollars to donuts they are selling you a bill of goods. And, the worst part is, they probably don't know it.

We have proven, effective, easy, and inexpensive methods of pool care. My SWCG has been super-successful for me for last season and this, because I had long mastered what we call the B-B-B method of pool care that Ben developed. B-B-B stands for Bleach, Borax and Baking Soda as three key ingredients to pool care. Add CYA (Stabilizer) and dry acid or Muriatic Acid and you have EVERYTHING you need.