Capacity and setup
Choose reservoir size without turning it into a time promise
Reservoir capacity is a space figure, not a time promise
A larger tank holds more water. It does not tell you how long to leave the fountain without inspection. Drinking, spills, evaporation, the operating minimum and the cleaning routine all affect the useful interval. A manufacturer battery-duration claim is a separate number again: a charged battery does not keep a reservoir full.
Compare capacity within the exact configuration
The Mini Flower 43735 has a 1.5-liter reservoir. Its compact size can be helpful where floor space is limited, but leaves less stored water than the larger models. The PIXI with steel top 43720 and Easy Clean 43621 are two-liter configurations.
The original Flower 43742, LED Flower and Steel Flower are three-liter models. The Dockstream 2 models and Dockstream RFID also specify three liters. That shared capacity does not give them the same flow controls, cleaning parts or identification features.
The standard PIXI page presents conflicting capacity figures. We do not choose the larger figure as a promise. If a confirmed minimum reservoir size is essential, use a model with an unambiguous specification or obtain confirmation for the exact standard PIXI package.
Leave room to refill without making a mess
Measure the filled reservoir's route to the sink as well as the place where it sits. Can you lift the top off, grasp the tank and carry it level? Can you return it without dragging a cable through the wet area? A detachable reservoir can simplify that handling while leaving the electrical base in place.
The new Easy Clean requires a particular restart after a low-water refill: its official instructions on the product page say to lift the reservoir from its base for at least five seconds before replacing it. If flow does not resume, follow the exact troubleshooting steps rather than repeatedly adding water above the indicated limit.
Know what remains accessible when circulation stops
Several PIXI and newer Flower configurations retain water in a shallow drinking area when off. The LED Flower has petal-shaped cups for that purpose. That residual water differs from a flowing stream, and it does not establish that the entire remaining reservoir is accessible without power.
A low-water shutdown is also different from a refill alert and from an available drinking supply. Treat it as a reason to inspect the unit. Do not wait for a stopped stream to become the household's only water-level check.
Use the first days to learn the refill routine
Check the water level and surface regularly, note the household's actual refill pattern and inspect after spills or unusual use. Multiple cats using one fountain can shorten that interval. An app reading is useful only within the device's stated tracking arrangement; it should not be used to infer that all tank loss belongs to a particular cat.
Choose enough capacity to make normal refills convenient while keeping the unit easy to carry and clean. The finder can combine a confirmed reservoir requirement with power and surface needs, so the largest tank does not become the whole decision.