50ppm is your call....I think it will cause some testing issues and may have some negative effects I'm not aware of. The only reason I suggested 35 was because I was fairly confidant you wouldn't get there. Now, because, you've killed many of the organics, you may well be able to get to 50ppm and I would not recommend it. I'd shoot for 30-35 max and lower still as your water clears. Others may disagree.