What kind of pump?

[Reefer Noob]

i wanted to try and make my own protein skimmer for a 29 gallon bio cube. I have a 55 gallon sump. I may add another 20gallon tank to the sump. But what kind of pump should I buy for my diy protein skimmer? My design will be based around that

 

[Feltman]

Maxijet pumps come with the attachments to add air lines and are fairly proven smaller pumps