Tunze Osmolator Nano

[asylumdown]

+1 on the optical sensor being a superior option. FWIW, I've modified a regular Tunze osmolator to run on my 4 gallon pico. It's an expensive way to do it, but it works like a charm. I did however have to ditch the emergency float cut-off to do it, but I'm confident enough in the sensor that I haven't lost any sleep over it.