225 TH/s is a nice, even 9x24.567 TH Fast-Hash One Platinum miners.
It goes from 65 TH (roughly 3x24.5 TH - could have been working out some bugs, bad chips, or hardware build issues), to 100 TH (roughly 4x24.5 TH), to 150 TH (roughly 6x24.5 TH), to 225 TH (roughly 9x24.5 Th)...
Whoever is mining is operating at roughly 2.25% of the global Bitcoin hash rate.
It's not ActM. I know this for a fact, as much as I would rather it be them.
Do you know who it is? Whoever it is is mining on your pool - the one you suggested Ken mine on.
They are adding in increments divisible by 25 TH.