macroalgae splitting apart

[bv_reefer]

i got this big bunch of red macroalgae called red weed, about a week ago and lately i've been finding a bunch of it's branches simply broken off and stuck to my powerhead and i don't understand whats going on, could the flow be too much? koralia 3 on the top right, and maxijet 900 on the top left, and the bunch of macroalgae is at the very bottom of the tank, are his branches possibly too long and need to be pruned? there about 3-4''