We bought a house with a 21ft round 52" high above ground pool. It was not winterized but a solar blanket was on it until two weeks ago when we pulled it off. We had the water tested at the local pool store and it was only low in a few things. long story short, we pulled the cover off and poured in two containers of liquid shock and stirred it up for a couple minutes. Now a week later it is green, full of living bugs, and there is a large accumulation of algae on the bottom (about the same as before but now all green instead of black). There are no leaves in my pool or backyard because it is a newer development with little trees.

The pool has water and a deck. We ordered a waterway 100sq ft cartridge filter and 1 hp pump which is arriving tomorrow. Before we hook this thing up and turn it on, should we be using liquid or granular shock? how much? I understand that we will need to vacuum the organics out and balance the chemistry of the pool. We have visited 3 different pool stores and they have all told us different things to do:
Store 1. Dump 1 case of liquid chlorine in and run pump and vacuum for a long time then test levels.
Store 2. Dump 2 cases of liquid chlorine in and vacuum until clear (12-24 hours) then test.
Store 3. Dump 2 pounds of powder shock in (with ph built in??) and also add a bottle of Pool Magic and run the vacuum and pump/filter for 24 hours then test levels.

Who is right? Are any of them right? I really wanted to do a saltwater system with this pool but because it is so swampy, and I have NO support from the pool store people, I am probably going to do chemicals this summer.

I have so many questions!!! lol! I would love if anyone could help me with anything and let me know if following these pool store people is okay.

thanks in advance,
Lisa