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CO₂

Regulator + solenoid

co2

Used for: Planted tanks, CO2 injection

Description

A CO2 regulator attaches to the gas cylinder, and a solenoid is an electric valve on the line that lets the gas through only while it is switched on. Laboratories that dose CO2 into aquaria use the pair, and they describe it plainly. A 2016 study of freshwater zebrafish fed its CO2-treated aquaria from a header tank that was bubbled with 100% CO2 gas using a solenoid valve controlled by a pH stat computer. A low-cost controller published in HardwareX in 2021 sends its signal through a relay to a 12 V normally closed electric solenoid valve; the relay module controls the solenoid valve power and ensures that it opens only when signaled, and the CO2 travels from a pressurized gas tank through the electric solenoid valve and finally to the aquarium. Its builders list the regulator as a separate purchase: compressed CO2 gas and a regulator costing from 50 to 400 US dollars are also required. A second open-source tank controller, from 2023, switches a CO2 addition device that its authors say is typically a solenoid-activated CO2 regulator, and in their own test the regulator was attached to a 5-pound CO2 gas cylinder. Those systems open the solenoid from a pH reading. The aquarium kit in our search that carries this row's parts is built for a timer instead: a regulator with dual pressure gauges and a 12V DC solenoid valve, which, combined with a timed socket, can automatically control the switch of CO2. The seller says the safety range is marked in green on the dial, that the regulator suits American standard CGA320 CO2 tanks, and that solenoid valves require regular maintenance and need to be cleaned when not working. None of these sources gives a working pressure or a bubble rate for a home tank, and this page does not.

Sources

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