If you can get a water sample tested and post the results back here, we can assist more. Test for:
Free Chlorine
Total Chlorine
pH
Total Alkalinity
Calcium Hardness
Cyanuric Acid

After treating your pool for algae, make sure you backwash your filter (or clean your cartridge, whichever the case is). Don't worry about adjusting alkalininty until after algae is cleared up, but definately bring your pH down so that the chlorine can be more effective.
Another thing, depending on what your cya and pH levels, you can use a tri-chlor shock treatment if cya is low and pH is high. Tri-chlor will somewhat balance that due to the low pH and cya nature of the tab. If Cya is high and pH is high, you can use bleach and muriatic acid (but not at the same time - do not mix these in a container!!!)
If calcium hardness is high, do not use any calcium hypochlorite based shock treatments.

So you can see why knowing what the current chemical levels are. From there, we can recommend the correct solution for you.