Now to deal with the surface scum and random floating pieces of cat hair...
I do feed

in the tank and have a protein / oil slick floating on the surface of the water. Stuck in the oil slick are pieces of floating cat hair... gross. The FX5 won't pick this up because the intake is deep in the water column (where it should be) to grab the turtle waste. I've been mopping up the oil slick with a paper towel on occasion but decided it was time to fix this problem for good. I need to skim the surface of the water and send it to a filter. I looked into modifying the FX5's intake so I could possibly take in water from deep in the tank as well as from the surface. I decided I didn't want to modify any of the FX5 parts in case I changed my mind about this later.
Through my internet searching, I discovered a really neat piece from Eheim. It's exactly what I wanted for the FX5... a dual intake. It has a regular strainer for deep in the tank + an opening for surface skimming. It's around $40.. not too bad but it won't fit on my FX5's giant tubing. However anyone reading this thread with an eheim, Rena XP 3/4, or even some of the generic filters should be able to use this eheim adapter. It's eheim part # 3535000.
Eheim Surface Skimmer

- eheim_surface_skimmer.jpg (8.55 KiB) Viewed 10748 times
I have one of the generic surface skimmer attachments laying around in a box of random unused aquarium parts. It's $9 new and made to go on to almost any filter (except my FX5 with the giant tubes)
So now I'm thinking of getting a second small filter to hook up to the surface skimmer attachment that I already have. I don't need much in the way of filtration or even water flow. This isn't my primary filter for keeping the water parameters in check and the water clear... the FX5 still does that. I just need something to take in the surface gunk and cat hair. I don't need any biological filtration for this...just some basic mechanical filration to grab the cat hair and some chemical (carbon or purigen) to grab the protein / oil slick.
Maybe a small Rena XP1/2? Maybe an XP3 and have a backup filter for other canisters in the house? Do I get a small eheim? Or do I get one of the generic sun/sun type ebay canisters because they're cheap? Even though I could hook this little skimmer thing up to a HOB like an aquaclear that I already have, I think the cat would mess with the HOB filter. A canister would work best.
Thoughts? Opinions??