Και για να αρχίσετε να ψάχνετε το google δείτε και αυτό...
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The pH is also a vital factor in nitrification. Maximum rates of nitrification occur at pH values above 7.2, peaking at 8.3 (a common pH for marine tanks) then falling at higher values. What surprised me was the rate at which the effectiveness of nitrification dropped in acidic pH values: to less than 50% optimal efficiency at pH 7.0, to just under 30% at pH 6.5, and to just over 10% of maximal efficiency at pH 6.0. At these low pH values, nitrifying bacteria don't die, they just stop metabolizing and reproducing. Of course in these acidic conditions, most of the toxic NH3 is ionized to non-toxic NH4. But I had been under the impression (and mentioned here) that the pH needed to drop quite low, below pH 4.8, more like the acidity of a peat bog rather than conditions in a home aquarium. Not so.>>
Η πηγή
εδώ.