Mostly I take care of freshwater fish for my kids. A 35gal bowffront has 2 fancy goldfish and EHEIM classic 350. The 20 gallon has some neon tetra,rasbora, and a bristlenose pleco with two HOB filters. The 5 gal is where they keep the assassin snails it has a fluval C2 HOB.
The 20 and the 5 have some live plants so I added some natural CO2 natural plant system from Nutrafin. I also had an API Nexx external canister filter it's been shutdown due to the leaks that arise every few months and seem to have no common cause.