Spectrapure has a slew of choices starting at $55 for the Power Liquid Level Controller which only has a small 1/2" clear probe in the water so is almost out of sight. LIQUID LEVEL CONTROLLERS I use the Ultra Precise ATO myself which comes with the same peristaltic pump as the Liter Meter. Its been very reliable. I think the Power Controller would be a great choice for a nano system since its so compact. I may have to invest in one myself for my 16G bowfront.