[Peter Finke]

Dear Bernd, the problem is not to produce one sex only but to prevent that. I remember that somebody complained that he had about fifty offspring of nagyi but all females. Unfortunately we are unable to give exact borderlines for temperature, acidity or humine concentration. The Most probable reason is that these factors form a joint system and one cannot view each of these separately. Therefore it is impossible to say e.g. “until 25 degrees Celsius males, above females.” I am sorry but it is a bit more difficult. So it is possible that one breeder with low temperatures and a pH near the neutral point has a majority of males, whereas his colleague with high temperatures and very low pH has the same result, but with other configurations of that values we get a different picture