Starting YANP (Yet ANother Project) in my aim to build individual controllers for the bulk of my tank functions and finally deprecate my APEX. As it stands, its solely responsible for heater control, and... controlling the CO2 pH in my calcium reactor.
(As a sidebar, its a companion to the other APEX replacement, the PerfectTemperatureController: https://www.reef2reef.com/threads/theatrus-perfect-temperature-controller.707407/ - I have the controller in testing right now, more updates soon!)
One of the commercial units which starts with "Carbon" and maybe ends in "Doser" utilizes a single Clippard EV mouse valve and a small little Appliance timer module with a twisty pot. Years ago I cloned this, into a very simple 555 timer project which was easy for others to build, and where the single most expensive part was the $40 Clippard solenoid valve.
www.reef2reef.com
Its a super simple setup, and I still use it in lieu of a needle valve for controlling the CO2 rate. Needle valves can be rock solid, but in my experience are usually frustrating to all end to both get set in place at very very slow flow rates, and will drift over time as temperatures change and CO2 pressures move. Since I hate needle valves, I back my initial little controller with the APEX performing a very coarse CO2 on/off. The number of cases where I've run without the Ca reactor producing any viable effulent way outnumber the cases where its run away and melted down (which has more or less never happened), I bias the control to have the Co2 system in the OFF state most of the time, and add CO2 in bursts here and there. It makes a messy pH graph, works, but also has a distinct cycling noise.
I'd like to upgrade that whole setup. The basics are simple:
- pH sensors. Preferrably two, either for tank+reactor, or in two different stages of the reactor (effulent vs internal if using a media scrubber section).
- Clippard valve. I'd like to do a test using the $20 more expensive Clippard EVP valve, which is a proportional valve which opens with a varying voltage, instead of the clicking on/off EV valves, which produce a subtle ticking sound to meter CO2 when actuated in short bursts.
- One or two 30PSI differential pressure sensors, connected between inlet and atmosphere (to monitor CO2 from the regulator) and inlet to outlet (to monitor if the reactor body is accepting CO2 or has backed up in some way, or if its extremely low has lost the peristaltic pump feeding it).
Controller is based on the ESP32, which I'm using in https://www.reef2reef.com/threads/all-in-one-led-controller-dimmer-driver-project.558930/ (see, Yet ANOTHER project
). The pH section is lifted directly from the Reef-Pi Pico base board and is isolated, with two inputs instead of one. Using the ESP32 lets it also have internet connectivity for alarms, and can be used in other integrations with Reef-Pi or other systems. Plus its cheap
The pH control can be made to run as a PID loop, to hit a particular pH in the reactor at all times with no swings.
A very very rough mechanical mock up is pictured below. The inlet and outlet ports aren't modeled yet, but this fits in a super compact little aluminum case, though the insides will have a decent chunk of snaking 1/8" Tygon tubing. Board will have a cutout to support the valve body, and I'm looking at good ways to mechanically mount it with a back of zip-ties and a bit of foam.
(As a sidebar, its a companion to the other APEX replacement, the PerfectTemperatureController: https://www.reef2reef.com/threads/theatrus-perfect-temperature-controller.707407/ - I have the controller in testing right now, more updates soon!)
One of the commercial units which starts with "Carbon" and maybe ends in "Doser" utilizes a single Clippard EV mouse valve and a small little Appliance timer module with a twisty pot. Years ago I cloned this, into a very simple 555 timer project which was easy for others to build, and where the single most expensive part was the $40 Clippard solenoid valve.
CO2 dosing controller for calcium reactor
Several years ago, I had a CO2 regulator from Carbon Doser / Aquarium Plants which has the unique feature of a "regulated" bubbles per second instead of a needle valve. Due to a depleted tank and back pressure from my reactor, it died a salt-watery death, or at least the main value portion - the...
www.reef2reef.com
Its a super simple setup, and I still use it in lieu of a needle valve for controlling the CO2 rate. Needle valves can be rock solid, but in my experience are usually frustrating to all end to both get set in place at very very slow flow rates, and will drift over time as temperatures change and CO2 pressures move. Since I hate needle valves, I back my initial little controller with the APEX performing a very coarse CO2 on/off. The number of cases where I've run without the Ca reactor producing any viable effulent way outnumber the cases where its run away and melted down (which has more or less never happened), I bias the control to have the Co2 system in the OFF state most of the time, and add CO2 in bursts here and there. It makes a messy pH graph, works, but also has a distinct cycling noise.
I'd like to upgrade that whole setup. The basics are simple:
- pH sensors. Preferrably two, either for tank+reactor, or in two different stages of the reactor (effulent vs internal if using a media scrubber section).
- Clippard valve. I'd like to do a test using the $20 more expensive Clippard EVP valve, which is a proportional valve which opens with a varying voltage, instead of the clicking on/off EV valves, which produce a subtle ticking sound to meter CO2 when actuated in short bursts.
Clippard EVP Electronic Proportional Valves | Clippard Knowledgebase
The EVP Series provides air or gas flow control, and varies the output flow based on the current input to the solenoid. The consistent gain of this valve provides a high degree of control for many applications. View more.
clippard.com
- One or two 30PSI differential pressure sensors, connected between inlet and atmosphere (to monitor CO2 from the regulator) and inlet to outlet (to monitor if the reactor body is accepting CO2 or has backed up in some way, or if its extremely low has lost the peristaltic pump feeding it).
Controller is based on the ESP32, which I'm using in https://www.reef2reef.com/threads/all-in-one-led-controller-dimmer-driver-project.558930/ (see, Yet ANOTHER project
). The pH section is lifted directly from the Reef-Pi Pico base board and is isolated, with two inputs instead of one. Using the ESP32 lets it also have internet connectivity for alarms, and can be used in other integrations with Reef-Pi or other systems. Plus its cheap The pH control can be made to run as a PID loop, to hit a particular pH in the reactor at all times with no swings.
A very very rough mechanical mock up is pictured below. The inlet and outlet ports aren't modeled yet, but this fits in a super compact little aluminum case, though the insides will have a decent chunk of snaking 1/8" Tygon tubing. Board will have a cutout to support the valve body, and I'm looking at good ways to mechanically mount it with a back of zip-ties and a bit of foam.
