I think I would be most concerned at this point with getting the pH below 8.6 for the safety of everything in your tank, including your fish. Your pH is sky high for saltwater.
This is the definitive guide to lowering pH, by RHF:
http://reefkeeping.com/issues/2005-03/rhf/
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Solutions to pH Problems
Some solutions to pH problems are peculiar to a specific cause, such as adding
vinegar to limewater, or using less of it. Some general solutions, however, are frequently effective. My recommendations on how to deal with high pH problems are detailed below.
The most benign way to reduce high pH is to aerate the water more. Whether the aquarium looks well-aerated or not, if the pH is above 8.5 and the alkalinity is not above 4 meq/L, then the aquarium is not fully equilibrated with carbon dioxide in the air. Equilibrating carbon dioxide can be much more difficult than equilibrating oxygen. Air contains very little carbon dioxide (about 350 ppm) relative to oxygen (210,000 ppm). Consequently, a lot more air needs to be driven through the water to introduce the same amount of carbon dioxide as oxygen. Perfect aeration will solve nearly any high pH problem, and will rarely cause any problem of its own.
That said, sufficient aeration is not always easily attained, and other methods can be useful. These other methods are:
A. Direct addition of carbon dioxide. Bottled soda water (seltzer) can be used to instantly reduce aquarium pH. Be sure to select unflavored soda water, and check the ingredients to be sure it doesn't contain anything that should be avoided (phosphate, etc). Many manufacturers list water and carbon dioxide as the only ingredients.
I recommend adding 6 mL of soda water per gallon of tank water to reduce pH by about 0.3 units. Add it to a high flow area away from organisms (such as in a sump). The local pH where it first is added will be very low. Going about this procedure slowly is better than proceeding too fast. If you do not have a sump, add it
especially slowly. Some soda water may have more, or less, carbon dioxide in it, and the lower the aquarium's alkalinity, the larger will be the pH drop. Also, the higher the pH, the smaller will be the pH drop, because the buffering of seawater declines steadily as the pH drops from about 9 to 7.5.
B. Direct addition of vinegar. Commercial distilled white vinegar (typically 5% acetic acid or "5% acidity") can be used to instantly reduce aquarium pH. Do not use wine vinegars as they may contain undesirable organics in addition to the acetic acid.
I recommend adding 1 mL of distilled white vinegar per gallon of tank water to initially reduce pH by about 0.3 units. Once again, add it to a high flow area away from organisms (such as in a sump). The local pH where it first is added will be very low. Going about this procedure slowly is better than proceeding too fast. If you do not have a sump, add it
especially slowly. The lower the aquarium's alkalinity, the larger will be the pH drop. Also, the higher the pH, the smaller will be the pH drop, because the buffering of seawater declines steadily as the pH drops from about 9 to 7.5. Remember, there may be an additional, later drop in pH as the vinegar is metabolized to carbon dioxide.
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Maybe get the wife to run to the store for seltzer?
The lack of precipitation is, unfortunately I think, a bad sign. It looks like precipitation is not removing the overdosed compounds from the water.
