Will you please give me some advice on a problem I am having with
using me VHS tape eraser?
I noticed that when I record over an erased tape, the new recording is
very dark with lots of red/orange.  There are brief portions of the
tape that record normally (about 10 seconds in every minute of tape
looks normal, the rest is very dark).

I followed the instructions, but maybe I am doing something wrong? 
Can you tell me why this happens and how to prevent it?

Thank you!

I presume a new tape does not produce the dark image with lots of
orange and red, so likely the erase is ok, but the degause is not.
Instead of what the instructions say, as the last steps, try moving
the tape cartrage and the Geneva away from each other very slowly in a
slowly twisting motion. The tape and Geneva should be at least one
meter apart before you turn off the power to the Geneva. Try it with
two people one twisting the tape and one twisting the Geneva, and try
twisting in various planes in hopes of finding a combination that
degauses completely.  Neil