Check out the below url. This lists the pool chemicals you can buy at a grocery store. You need to get the ph right before anything else in my opinion, otherwise your chlorine will disappear in a hurry. 20 muleteam borax can lower your ph.
I would keep my pump running continuously while I brush, backwash. Preceed this with a good dose of "poly60". You can get this at walmart. It is the only thing to combat mustard algae which you might have. This below link is only one tip of the ten. Check it out and good luck!


http://www.poolsolutions.com/tips/tip02.html