For at undgå separering af sedimentets bestanddele og resuspension af fint materiale under tilsætningen af testvand i vandsøjlen, kan sedimentet overdækkes med en plastplade, mens vandet hældes i. Plastpladen fjernes derefter straks.
To avoid separation of sediment ingredients and re-suspension of fine material during addition of test water in the water column, the sediment can be covered with a plastic disc while water is poured onto it, and the disc is removed immediately afterwards.