Powerhead for 20g

[scarf]

I think I'm getting a fair few deadspots in my aquarium. I'm pretty much just relying on my in hood filter + sponge filter for circulation which is quite limited due to a rather large piece of driftwood in my tank. Thus, I'm thinking of getting a powerhead. Only range I have access to is Hagen Aquaclear. Which powerhead (model) would you guys recommend for my tank? (Dimensions - 51x35x54cm - 20" x 13.7" x 21.2")

Btw, this is for my goldfish tank.

Thanks.

 

[Hoovercat]

I've got a 201 on my 10 gal. and usually keep the flow turned way down. The 201 is rated for a 20+ gallon tank but it's the smallest aquaclear unit.

 

[scarf]

I'm just thinking of getting the 301.

Does any1 have an opinion to the usefulness of the quick filter attachment to the powerhead?

 

[scarf]

Also, does it have to be that specific filter medium or has any1 succeeded in substituting it (with for eg, filter floss)?