I found an ac 50 for $30. I might put it with my tetra 45. That should be goodAll filters, even sponge filter have the potential to leak. But if you use a good check valve, a sponge might be your safest bet. I’ve flooded my house with a canister before( an eel pushed the return hose out while I was away. So a sponge would be the safest, then a high quality HOB and then a canister IMO