Mustard Algae Need Help!

[Dproctor]

I have had my pool (27' above ground) for 12 years. The past few years I have had a problem with Mustard Algae. The pool place sold me 2 bottles of yellow rid and a 5 lb bottle of shock. I did that about a week and half ago. I have vacuumed to waste 2 different times and actually bought one more bottle of yellow rid and have used it as well, followed by a few bags of shock. There is still a tad of the "dust" that she said was probably mustard algae on the bottom and I plan on vacuuming it to waste tomorrow. Problem is I still can't get chlorine levels up or PH up in my pool. Tonight, I added 1 bottle of alkalinity increaser, 2 bags of shock, and quite of bit of algaecide so I don't know what the correct levels read at this time and now it's getting ready to storm! UGH! Any way.... question is How in the world can I get rid of this mustard algae?? And what in the world do I need to do to up my PH and get my chlorine up?.... I used the strips and the test kit and both show NO chlorine and PH was 6.8 (before I put all that stuff in it mentioned above.) Water is clear til I add shock, then it's green for an hours or so. Your help is GREATLY APPRECIATED!!! After 12 years you'd think I'd know something but every year I seem to have some new problem.