Anyone getting unstable readings from HW-038 after long use?

[kasuo]

I’ve been testing the water level sensor HW-038 with my Arduino setup for continuous tank monitoring, but after a few hours submerged, the analog values start drifting. Has anyone found a reliable way to stabilize the output—like using a coating, resistor adjustment, or calibration routine?

[linux_rulezz]

Throw out this piece of shit and buy capacitive or inductive level-meter.
Or even something like this. A line of hall-sensors activating by floating magnet, works like a variable resistor with resistance changed by steps.

[Ult1mat3X]

That's a classic issue with the HW-038—it’s just not built for 24/7 submersion. Electrolysis eats the tracks, and mineral buildup causes that annoying drift.
Here is the quickest way to fix it:
Stop Constant Power: Connect the sensor's VCC to a digital pin on your Arduino. Only flip it HIGH for 20ms when you need a reading, then turn it off. This kills the electrolysis instantly.
Software Smoothing: Average about 10–20 readings in your code to filter out the noise.
Seal the Top: Apply some acrylic lacquer or clear nail polish to the top part of the PCB (keep the sensing traces clean!) to prevent moisture from creeping into the electronics.