Yeah, I'd lean more toward the 50 ppm cya for your situation. I wouldn't worry about borax. Even strong borax solutions are no more injurous to your skin than salt water. As for ingesting it, well, you have to take into account dilution. 1 ppm is equivalent to 1 drop of ink in a 40 gallon barrel. I'd be far more concerned about the low Cl levels and subsequent bacterial blooms rather than slurping down a very dilute cocktail of pool chems!

Michael