Been there and done that!
did you have problems or leaking problems after connected another kind of hoses to the quick release system of your fluval?
I have a Fluvall 405 and was worried about leaking at the quick connects as well.
My local aquarium supplier showed me what to do.
You cannot cut the ribbed tubing that comes with the filter and make a really water tight connection. The inlet and outlet devices connected to them are really very low pressure and even if they leak a little, they are in your tank anyway.
Here is what you do.
Get some 5/8" ID tubing. Don't get braided or heavy wall tubing as you will not have a run more than 1" of 5/8" tubing. You don't need much 5/8" tubing, 2 ft. is probably a lot. You also need two 5/8" Tee's.
Use a short piece of 5/8' tubing to connect the two tee's top to top like this: TT. Use screw down hose clamps to secure the tubing. There is a size that is perfect for standard unbraided 5/8" tubing that will give you a really positive seal.
The base of the tee's will be the inlet and outlet to your UV.
Use a second piece of 5/8" tubing to connect the top of one tee to the Fluvall.
The actual filter outlet from the canister is a metric size and is just a hair larger than the 5/8 tubing; so, it will be a little tight putting it on. Use the locking nut on the filter to clamp the hose in place.
Now take your old outlet hose and place it on the other tee top. You will have to use a hose clamp here because of the difference in metric size. If you don't, the hose will slip off in use. Cut the ribbed Fluvall hose down at the other end so it fits with the new configuration and reconnect to your outlet fitting. You now have an inlet port and outlet port to your UV.
Here is some thing to think about when you do your plumbing.
A UV filter is only effective if the flow rate is below some maximum amount. I was worried about this when I installed my UV and added a shut off ball valve to reduce the flow. It turned out that the actual maximum flow through my UV was below the limit and I didn't need the shut off. The inlet and outlet to my UV is 3/8" and acts as a flow restriction to the UV. You should check the flow rate through your UV after you install it.