Hi bro! what's up?
Here is the screen shot of the Twixtor settings:

as you see i key framed some parameters in different parts. and the speed changes from 100 to 0 which fakes <2000fps!
As you mentioned the black background helped but Twixtor still had lots of problems in faking many frames coz of the random direction of the splashing water...it looks so weird with so many wrong frames if i apply Twixtor to the whole footage, i could only apply it to a very limited short part with the speed parameter going down to zero..
Thank you