“Finding a good auto-top-off (ATO) for an open-top planted aquarium is surprisingly difficult. Most ATO kits are meant to sit in a sump, so their optical or float sensor has to be mounted several centimetres below the rim; that forces you to run the display tank with a low water line.
This little unit addresses the problem. The compact sensor can be mounted right at the desired water level inside the main tank, so the surface stays exactly where you want it—no big gap, no extra hardware hanging over the edge.
What I like
• Complete package: controller, tiny pump, hose and fittings are all in the box—just add a reservoir of RO/tap water.
• Accurate: after a month of use, the water line drifts by no more than 2 mm.
• Reliable: no false triggers from splashing or plant movement.
• Fair price for the convenience it adds to a high-tech, CO₂-injected aquarium.
Bottom line
If you keep an open-top planted tank and want the convenience of automatic top-off without lowering your water line, this sensor is well worth considering.”
