Время диспергирования gen.

[x-z]

Время диспергирования, после которого не происходило существенного (более 5 %) изменения турбидности, принималось как достаточное.

Dispersion duration not significantly changing turbidity level was deemed sufficient.

?

[Karabas]

Я бы вместо duration использовала period

[Анна Ф]

The dispersion period after (following) which turbidity had not changed considerably (by more than 5%) was taken as sufficient.
Я тоже подумала про "period".
The dispersion period followed by an inconsiderable (insignificant) change of turbidity (less than 5%) was taken as sufficient.

[x-z]

The dispersion period after (following) which turbidity had not changed considerably (by more than 5%) was taken as sufficient.

Это вообще не-не. Откуда там Past Perfect взялся?

The dispersion period followed by an inconsiderable (insignificant) change of turbidity (less than 5%) was taken as sufficient.

I like this one.

Thanks.

[Анна Ф]

Я "утрясла" правильный вариант, а старый не стерла )))
Да, тот, который внизу - итоговый, как подсказка ))

[x-z]

GraTHias.

[Rengo]

The length of dispersion process such that it caused no significant (above 5%) changes in turbidity was taken as adequate.

[Rengo]

sorry, " A length of ... etc"