



I built a super simple gravity-fed auto top-off for my tank using a mason jar and a 3D printed mounting lid.
The jar sits inverted on a custom printed mount and replenishes water as it evaporates — no pumps, no floats, no power. Just atmospheric pressure doing its thing. When the tank level drops, water feeds in automatically until it reseals.
This is on a planted nano-style setup so I just wanted something dumb-simple and reliable without adding another device to fail or clog.
I know it’s not a full ATO solution for large systems, but for evaporation compensation it’s been working surprisingly well so far.
Curious what you guys think — anything you would improve or change about this approach?
Posted by flyp_nip
2 Comments
stl?
This is dope. I really like this idea. Can you share the model to print?