fully automating a tank

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Well if your keeping it, lights should be already on a timer and heater on a thermostat or controller. Advantage of a controller or even something as simple as a Ranco is they can control the heater and a fan for evaporation cooling.

Rather than manually dosing 2-part, can use a dual channel dosing pump, GreenSpottedPuffer has a good deal on his or consider a Ca reactor.

ATO is though one of the greatest things. Can be a simple $10 humidifier float and reservoir or live on the edge and connect directly to a ro/di unit.