Hi Pantry,
As far as I am aware, option to define filters is not available in Webi.
Do you see any filter after conversion?
What you can do is you can define a variable as
[Week Ending Date3]
=[Start_Dt_4_Tbl] BETWEEN [End_Dt]
Drag it to the block as Week Ending column and remove the null value rows by putting filter as [Week Ending Date3] is not null.
Regards,
Yuvraj