RPi 3 Power issue with powered HDD

Hi
It seems I have a unique problem. All the threads I searched relate to USB powered external HDD. I have a powered Verbatim extenal HDD but I still get the rainbow squares of power supply problems. Sometime yellow but most of the time red, with visible distorting of video. As I understand it, the HDD should take minimal power form the Rpi’s USB port?

On it’s own, the Pi works fine, video add-ons works fine, it’s just when watching videos from the external HDD.

It’s a Rpi3 model B with a Rpi Power adapter and a powered Verbatim 1TB external HDD.

Will a powered USB hub make a difference?

Thanks for any help or tips.