We stock overflow systems that work with standard sized “off the shelf” aquariums, as well as any rimless tank over 28″ wide. Typically, we recommend they be used on anything from a 29 gallon all the way to the 300DD. They can also be used on almost any sized custom aquarium up to around 400 gallons. They offer a wide performance envelop as well. They can be used to produce flows from 1 GPH all the way up to and over 3000 GPH.