The results show that the number of agglutinated foraminifers per gram strongly vary between 0.1 and 7.8 with use of standard micropaleontological methods. With application of formic acid, more agglutinated foraminifers per gram are obtained than with any other tested method. The number of agglutinated foraminifers per gram is 1.5 to 211.0 times higher in formic acid treated residues. Furthermore, with use of standard micropaleontological methods at least 2/3 of agglutinated foraminiferal genera and species are completely missing in these sedimentological settings. Consequently, standard micropaleontological methods are not applicable to study the whole agglutinated foraminiferal fauna, and a bias of knowledge and utility of agglutinated foraminifers in these sedimentological settings is obvious. A separate application of both acetic acid + Copper(II) sulfate and formic acid on samples is suggested for studies on the whole foraminiferal fauna, and a precise description of the applied method in studies is suggested.