I also have a high GH at around 230ppm but GH isn't as bad as PH that high. I would Keep doseing with PH minus until you get it down. Not sure about the other plants, but Swords like it around 7.0 to 7.5. I have a community tank so I try to keep it at 6.5 PH. GH will go down after frequent water changes. I've heard people say putting Peat Moss in your filter will help with GH, but I've never tried it.
I've been told plants need anywhere from 8 to 12 hours of light. If you are trying to get rid of the Algae you need to get rid of either their food or their light. turning off the lights will definately kill the algae, but your plants will die too. My last resort after an algae bloom was to turn the lights off for about 2 months until the tank was spotless, then start over. If you up the light time to 12 hours, hopefully the plants will start growing again and leave the algae in the dust.