You should have put the borax in before the floc. It is not good to let the acidic water lay on the vinyl liner. Since you keep testing 6.8, and used a lot of stain treatment, the ph may even be lower than 6.8. If it were my pool I would vacuum to waste what you can on the bottom. This will probably stir up some sediment, don't worry. After you vacuum to waste, add more fill water, ADD BORAX, keep filter running, check ph and don't stop ADDING BORAX until you reach a ph of at least 7.0 - leave 2 hours in between tests. When you get the ph back up, turn the filter off and let the water settle. You should still have enough floc in there to continue the process. Leave the filter off till you see more clearing of the water, even if you go to 24 hours. THen vacuum to waste again, or filter if the water is too expensive. I would really try to vacuum to waste to get it out of there - make sure you backwash the filter well if you just vacuum to filter. If the water is still cloudy, turn the filter off over night. Keep doing this until the water clears. The important thing is to get the ph back up to 7, the alkalinity back down (keep your return jets bubbling on the water as much as you can till you get the fountain). Get your water checked, and post numbers. Once you get the water rebalanced, you will be fine - Something is suspended in the water making it cloudy, It will take time to get it all filtered out - you just need some patience. You don't want to shock yet in case it is metals that are suspended in the water, that will fall out if the chlorine gets too high. It will just take time, but get the ph up