The Typhoon models are more for aquariums with higher volume needs. They come with standard filters and a vertical DI* (6,800 grains capacity). The Compact reefkeeper models are more for aquariums with lower volume needs (100 and below gallon tanks). These can be used for larger aquariums (especially if space is an issue), but the DI might exhaust faster. This is because the use the in-line DI* (3,400 grains capacity). The Dual Home Reef models are a good step if you have both aquarium needs as well as a need for drinking water. While the old and new style models use the in-line DI filters*, the Hurricane model uses a vertical DI*. As with most DI units, a trash can or other open-storage tank is used for the DI water. With the Dual Home Reef units, a pressurized storage tank is included for the drinking water, but the DI line is separate from it. Though you can use the pressure tank for the DI storage, the high flow coming out of a pressure tank will cause a DI to exhaust faster. For calculations on how long a DI will last, please look at the FAQ for the DI filters.