Calcium deposits?

[chem geek]

Larry,

For fastest results, run the spa's air pump. The more aeration the better, unless you want to wait longer for the pH to rise (and TA to drop when you add acid). You should also make sure you get good mixing between your spa and pool water -- otherwise the pH rise, add acid, pH/TA drop process will happen much more in your spa instead of your pool.

Richard