So a few days ago I decided to add a divider to my 10 gal tank so my girls would stop pulling each others fins off!... I also ended up adding a new filter :) Now I'm just waiting to put them in the tank :D They are going to love it! Below are a few pictures.
To build the divider I just used a piece of plexiglass and drilled a bunch of holes in it. Then attached it to the tank with some clear aquarium silicone.
I found some plexiglass(26"x16") at Homedepot for $8 And a tube of silicone for $3.99.
As for the new filter I went with: Cascade Canister 500
From amazon.com for $68. It's a bit overkill for my 10gal but the flow is adjustable and it does a good job of spreading the water across the whole tank with the spray bar.