Ahhhhh... now I gotcha...
most Powerheads have suction cups to anchor them to a wall... Koralia powerheads (which I like) have a suction cup and a magnet combo to anchor them... very small powerheads can simply be set in place without anchoring (just be sure they are not sucking up sand if you use sand as substrate)...
Have you bought the powerhead yet? If so it should be apparent how to anchor it... naming the brand you bought or are considering will help other's give specific advice to the one you have or are considering...
I wouild not anchor it to the AC 70 HOB's intake though... instead I would shoot the stream of water toward the intake to help move waste/debris toward the filter...
most Powerheads have suction cups to anchor them to a wall... Koralia powerheads (which I like) have a suction cup and a magnet combo to anchor them... very small powerheads can simply be set in place without anchoring (just be sure they are not sucking up sand if you use sand as substrate)...
Have you bought the powerhead yet? If so it should be apparent how to anchor it... naming the brand you bought or are considering will help other's give specific advice to the one you have or are considering...
I wouild not anchor it to the AC 70 HOB's intake though... instead I would shoot the stream of water toward the intake to help move waste/debris toward the filter...