Randy Holmes-Farley
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Thanks for the follow-up, Randy
So it will still leach until saturation? What is the limit?
The saturation limit of aluminum in seawater is not a single number as it will vary with pH and alkalinity and other things in solution, and I do not have a way to look up the exact value.
In the article below, I gave this estimate based on known freshwater data:
The maximum solubility of aluminum at pH 8.2 in freshwater is about 2.7 ppm. That is, at concentrations higher than that, the aluminum will precipitate as amorphous aluminum hydroxide. I expect the solubility to be similar or higher in seawater, where complexation to organics may increase the solubility. Consequently, the solubility in both the oceans and in aquaria (as will be seen below) is apparently not typically limited by the solubility of aluminum hydroxide itself.
http://www.advancedaquarist.com/2003/7/chemistry