Hydros dual doser

[Hooz]

Those are sweet, but I got an 8 pack of the Kamoer pumps for half the cost of one of those pumps. You can slow them down using the drive voltage to tune the flow rate. At the 3.3v I'm giving them, they'll do 3.1ml/min or, in Hydros terms (2.5 second minimum on/off time), they can be dialed down to a .13ml minimum dose.

If I need smaller doses than that, I'll do it by hand and/or re-evaluate whether I really need it or not.

Just be aware that voltage or pwm control of a DC doser can be inconsistent at lower voltages. If precision and consistency is key in the application, gear reduction of a doser while being driven at full voltage is always prefered.

These pumps are designed to run at 3.3v (they sell the pumps in several voltage/flow rate configurations), and I'm using high quality, fixed voltage buck convertors to step down the 12v input to 3.3v. No dials or PWM control, just steady, fixed voltage.

I left all the inputs and relay board at 12v, and put the buck convertors right before each pump. That way, I can swap one or all of them to different (up to 12v) pumps in the future if needed.