pH at 6.8 worries me! Most pool pH tests have 6.8 or 7 as the minimum reading, that probably really means somewhere between 4 and 6.8. Get your pH up to something higher than the lowest reading your kit will measure. Greater than 7 and less than 8 is the initial target.

What is your chlorine level? If you don't want a green pool (and who does), free chlorine levels must be maintained as a ratio of CYA. 3ppm with zero CYA is a good target. 10ppm with no CYA will likely damage high and low end swimwear, mid - level swimwear seems to fare somewhat better.