Definitely there is no longer any damage being done by the pH or vinegar, but if the pH was 9 for long enough, yes, it can be a problem.
Is the tank milky white?
There is nothing more that is useful to do now but wait, and maybe monitor ammonia if things begin to die. Treat it like a limewater overdose, which I advise on here:
What is that Precipitate in My Reef Aquarium?
http://reefkeeping.com/issues/2005-07/rhf/index.htm
Precipitates from Overdosing Limewater
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When limewater is substantially overdosed, the transient precipitation of magnesium hydroxide from normal use may not be the only precipitate that forms. If the pH becomes elevated and stays that way long enough, calcium carbonate can precipitate throughout the water column. In such situations, the entire aquarium can become very cloudy, looking almost like skim milk (Figures 9 and 10). Such precipitation events have the beneficial effect of lowering the pH and alkalinity that were raised by the overdose, limiting the ongoing damage that takes place. In many cases, there is no apparent harm after a day or two, but in a few rare cases, when the overdose was especially extensive, a tank crash can occur, killing many organisms.
The following important points should help in dealing with a limewater overdose:
1. Don't panic! These overdoses do not usually cause a tank to crash.
2. The primary concern is pH. If the pH is 8.6 or lower, you need not do anything. If the pH is above 8.6, then reducing the pH is the priority. Direct addition of vinegar or soda water is a good way to accomplish this goal. Either one mL of distilled white vinegar, or six mL of soda water, per gallon of tank water will give an initial pH drop of about 0.3 pH units. Add either to a high flow area that is away from organisms (e.g., a sump).
3. Do not bother to measure calcium or alkalinity while the tank is cloudy. The solid calcium carbonate particles will dissolve in an alkalinity test, and all of the carbonate in them will be counted as if it were in solution and part of "alkalinity." The same may happen to some extent with calcium tests. Wait until the water clears, and at that point, alkalinity is more likely to be low than high. Calcium will likely be mostly unchanged.
4. The particles themselves will typically settle out and disappear from view over a period of 1-4 days. They do not appear to cause long term detrimental effects to tank organisms.
5. Water changes are not necessarily beneficial or needed in response to a limewater overdose.
:uzi::fish1:Fish totally unfazed .
