Not Carl, but maybe I will do.

Keep adding muriatic acid in front of a return jet - not in a big slug in the deep end. Keep working at it until you get the ph down to 7.4-7.6. To kill the algae, you need to shock your pool up to 15 and try and hold it at that level. In a pool your size, every 3 quart jug of plain, unscented household bleach will raise your cl by 2ppm. Test the water at least 2x (and 3x is better) a day and each time, add enough bleach to raise your cl level back up to 15. You can't let the cl level yo-yo up and down or you'll never kill the algae. It will take several doses, but if you will do this, it should kill the algae. Leave your alk alone. 120 is just fine. Brush the floor and walls and run your pump 24/7 while you are trying to clear the water. I am not a SWG person, so I can't help you with that part. At any rate, if you keep that chlorine level up, your water will clear. Hope this helps.