I have the TF100 and since we have opened the pool in May I have not been able to keep the PH or Alkalinity in the appropriate range. PH normally runs 7.8 or higher and TA is always around 170. I have been using muriatic acid in the gallon jugs and putting in what the calculator says to use. PH goes down for a while but TA never seems to and then PH just climbs right back up. Not sure what to do. I have probably put in about 4 gallons so far since mid May but my numbers are still the same as when I started.