earlier I asked about how to know the aluminium sulfate solubility as function of the ph (see the previous question here). I found this diagram on the page 57 of
Rubin, A. J., & Hayden, P. L. (1973). Studies on the Hydrolysis and Precipitation of Aluminum (III).
But I'm a little confused about the interpretation. Is the $\mathrm{Al_{2}(SO_{4})_{3}}$ insoluble between pH 5 and 7?. What will be the correct interpretation of this diagram?