If 250 is the minimum amount of developer needed, and you're diluting 1:3 you need a tank that can hold 1 L, otherwise the film doesn't have enough developer available.
If the tank only holds 295 ml, there is not enough developer available to do the job, even though the ratio of what's there is 1:3.
To the OP, what are you looking to accomplish with the 1:3 dilution?
Who says 250ml is the minimum amount of neat developer needed to develop one 35mm film. That would imply that I need 500ml of final working solution to develop at 1:1, which I don't.