I have one canister filter running through my overflow on my tank. I was looking to buy some replacement tubing and fittings as I just rushed out and bought what I could find when I first set it up. I managed to get everything right and it fit and works and has been for several months, I just want to clean it up a little. The only problem is I can't remember what size tubes I got. What size tube will I need to hook to the inflow and outflow bulkheads on the overflow? These are just your average bulkheads that come with the All-Glass overflow kit. Also I know the ID of the tubes on the Rena Filstar series is 5/8" ID, but generally speaking do you get the fittings slightly larger say at 3/4". I am thinking I will need 2 fittings for each tube, both with an insert on one end and one with a male connector and the other with a female connector 2 connect the 2 different sized tubes together. I just need to make sure that I get everything the correct size.