I was told by a member on another forum about two Taylor test kits that have larger ranges: Taylor K-1285-1 and Taylor K-1592. However, these really aren't necessary since this problem of being so far out of range is usually quite rare and generally one can just try using amounts of acid or base to move up to 0.5 pH units at a time until one gets into range.

The Pool Calculator can be used to calculate dosages, but for moving the pH these calculations are approximate. I have the accurate calculations in the Pool Equations spreadsheet, but it's not easy to use.

Also, if one has the acid and base demand tests in the Taylor K-2006 or equivalent kit, then that can be used to determine the amounts needed. Generally, these tests aren't that useful because they are too coarse, but when the pH is out of range and larger adjustments are needed, then these tests will work better.

Richard