If this is your pump
then it only does 100 GPH
with a 4 ft head which isn't enough flow to bother with IMO
As Ziggy said a Mag 5 or 7 pump would be a better option depending on what your overflow can handle. You want to match your GPH
with a 4-5 ft head as closely as possible to your overflows rated GPH
A sump should only be filled 2/3rds full to allow for back flow from the tank when the pump goes off (due to maintenance or power failure) so a 10 gal
tank will only hold around 6-7 gal
which is better then nothing but a larger sump would help.
Of course your kind of limited if you have a standard 55 gal
tank stand which is only 11"-12.5" wide internally so depending on your tank stand's internal measurements you may be able to get a 20 gallon High or long tank in it.