Aquaclear 50 would be good for a HOB filter. I love the basket and it's easy to modify. Even with freshwater I like to get a slightly larger than recommended filtration for a system. My 20L Planted I have an AquaClear 70, just turned down to the lowest setting. I also run an AquaClear 20 on my daughters 10 gallon Paly tank. Great filtration with a ability to change amount of flow is what I always look at. If not, a great canister filter is always the way to go if you have the room.