Which AquaClear filter is best on on 55 gal tank with an Eheim 2213?

HI,

I have a 55 gallon tank with 5 fancy goldfish (Black Moors, Lion Head,
etc.)in the tank along with a few live plants. I currently use an
Eheim 2213 canister filter, which appears to provide sufficient
filtering capacity for this load. I now want to add an Aquaclear
hang-on filter to my tank to provide some additional benefits. These
include (1) the abiltiy to periodically use certain media, such as
phosphate pads and carbon, on a short term basis without having to
open the canister too often,(2)provide some redundancy/back-up, and
(3) allow the addition of a few more fancy goldfish.

The AquaClear 300 or 500 are often recommended for a 55 gal tank.
However, I am concerned that these filters(in conjuction with the
Eheim 2213) will cause too much turbulance in the water for my poorly
swimming fancy GF.  I understand that fancy goldfish don't like too
much water movement. I used an AquaClear Mini on my previous 10 gallon
tank and liked the design, so prefer to stick with the AquaClears.

Any opinions on using the AquaClear 300 or 500 on my setup. What about
the smaller AquaClear 150 or 200 to minimise water movement?

Thanks for any opinions