I have a friend who opened up to low PH and he uses sticks(he wont buy the TFkit) and his PH is around 6.2. When using pool math for a 28000 Gallon pool, the now and goal part of pool math says add 711 oz of Twenty mule team borax, to raise it to 6.8. The effects of adding chemicals says it will raise it 1.3, which would make it about 7.4. What am I missing???