Eheim, Fluval, Magnum, Proquatics and Rena Filstar all produce excellent canister filters for saltwater tanks. All offer high quality filter for reasonable prices.
Hagen Fluval canister filters receive high marks because they are easy to clean. The Marineland Magnum filter is also popular, due in part to the bottom-mounted motor.
I suggest the Rena Filstar canister filters. They are relatively cheap compared to some other canister filters. They work great and they are what I have used when I need canister filters. As with any canister filters they do need to be cleaned often depending on the system.
The thing to do would be to do research into sumps or refugiums. It increases the water surface area, and space to add other equipment and chemicals as needed.
The highest rated salt water aquarium canister filter is A Aquarium Pharmaceuticals RENA FilStar xP3 canister filter. They can be pruchased for under $200. 00. One year Manufacturer`s Warranty. For aquariums up to 175 gal and has a flow rate of 350gph
