What is the absolute largest amount of water I can change out safely withoutt causing more damage to levels in my 32 gallon to offset the high Alkalinity (26), Calc (530) ? Every other Parma is spot on . Salinity 1.024, Ph 8.2 RO water is used along with Instant ocean reef crystals. All corals (Duncans, finger leather, acan, flame torch and trumpets) are 1/4 way open.