time frame and nutes

I am using beastie blooms 0-50-30 and in the 3rd week of bloom what week should Iswitch to cha ching 9-50-10

I don't use any of that stuff, but I do know you should be using a fert with some N in flower, usually all the way through. If I had your ferts, I'd use the 9-50-10 for the first 4-5 weeks and then switch to the 0-5-3 bomb for just a couple weeks at the end. Hell, I'd prolly just keep with the first stuff all the way to flush, if you do that sort of thing.