Even certain air coolers could honestly keep it cool.
But for what you're doing, go for a custom loop. They look amazing and they're so easy to customize. You can get whatever rad you want, whatever reservoir size, etc.
Closed loop watercoolers are never worth it, a Noctua D14 will cool just as well as an H100 and for cheaper, if you want to hit 5ghz badly go for an actual custom watercooling loop. ~$250-largenumber.
You can make a closed loop for a cheaper price, just requires more time and some compromise. Rip a heatercore from a car and boom. There's your radiator. Reservoir can be any closed contained really, and then just get a water pump. The only thing you need to buy that is made specifically for watercooling a computer is the waterblock, and I wouldn't skimp on it.
Like i said in the Other post the XSPC raystrom kits are about as expensive as the Kracken x60 and will outperform it, plus you could add on to the loop when you please.
Do you happen to know how much of a difference in tempatures the Kraken is to the H80i,and how much cooler the XSPC raystorm is to the Kraken and the H80i?