Sediment transport / initial bed conditions

I am trying to set a sediment transport model.
I defined 3 sediment classes with concentrations (in Sediment and Sediment Properties tab), then using “create uniform bed” i am trying to define 1 layer of sediments with 1/3 mass fractions of each sediment class. But I keep getting an error “Sediment mass fractions do not add up to 1” and later -“Bad or Wrong SedBedTop file! Parameter 6 activated do not match”. I know I am doing something wrong, I just can’t figure out what.
Also, I guess I am bit confused regarding concentration values of sediments. User can define sediment concentration while describing sediment class, and also at the boundary conditions (for Coh and NonCoh sediments). What are concentrations defined in class of sediments used for?
Many thanks!
Maria K

please, disregard the first paragraph, i found a solution