demifelix;999211 wrote: Yes it is Dave if I understand you correctly. There's a small tubing from the top of the 1st chamber (where the recir pump first pumps water and CO2 into that chamber) that connects to the bottom of the 2nd chamber. From this design, it looks like the effluent from the 1st chamber is very low pH since it just got mixed with the incoming CO2.
So, now I understand how this works conceptually, that leads me to another question: how do we control the solenoid using Reefkeeper elite? Should we have the RKE monitors the pH and turn on the solenoid when pH is low and turn off when pH reaches desirable level, or should the solenoid be put on timer to run during the day time and off during night time to avoid pH swings? or should the entire CA reactor be run 24/7 regardless? What's the best way to achieve ultimate stability? I have been dosing for months now and everything is so stable and I don't want to risk anything by doing something silly with my CA reactor.
You should have a pH probe port in the reactor lid to monitor the pH inside the first chamber (recirculation pump chamber). I have an RKE as well. You set the PC4 outlet the CO2 solenoid is hooked up to act as a controller, then tie the controller to the SL1 or SL2 module the reactor pH probe is connected to, and have it energize when the pH is above whatever setpoint you choose. 6.5 is a good start point, then set the hysteresis to .01 or .02. You add CO2 when the pH is above the setpoint, and it cuts off when the pH goes below the setpoint. The smaller your hysteresis, the narrower your control parameters, so the more stable the alkalinity of the tank should be.
In regards to what is running 24/7, everything is, meaning there is always effluent going through the reactor, the recirculation pump is always on, and the RKE is controlling the CO2 gas 24/7, turning it on or off as needed, according to the pH of the inside of the calcium reactor.
Read these cut 'n pastes from another thread I just commented in, as it applies to your setup as well:
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The main difference, cost aside, between calcium reactors and dosing, and the factor that I think makes calcium reactors a good choice, is when you are dissolving media, you are dissolving and releasing not only bicarbonates and calcium, but also magnesium, and trace elements as they were laid down by the corals that originally took them up before they became reactor media, so you have all three: bicarbonate, calcium, and magnesium, and proper traces released in the proper proportions in a calcium reactor setup. It costs a bit more initially, but the cost evens out over a couple years. Manual dosing does not provide that in an all in one type setup, just bicarbonate and calcium.
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Once you have the reactor dialed in, you don't have to do a lot to it. Main thing is to ensure a consistent flow rate of about 60 ml/ min through the reactor (give or take), then use a bubble rate of one bubble CO2 per second (50-60 per minute), then set a reactor pH set point of 6.5 or so to start, then monitor your KH according to your goals and adjust the pH set point up or down accordingly. The above settings are not in stone, but are a good starting point and what is usually recommended by reactor manufacturers as starting points as well.
Main thing is to understand the relationship between pH set point and system KH. The lower the reactor set point, the more CO2 will be bubbled into the reactor, and the more bicarbonates, Ca and Mag will be released as the media is dissolved at a faster rate, the higher the reactor set point, the opposite happens.
For example, if you want to keep a system KH of 9, and at your above settings, over a couple weeks your KH goes down to 8, then you lower the pH set point of the reactor to 6.4 from 6.5, which bubbles more CO2 into the reactor, dissolving more media and releasing more bicarbonates, thereby raising the KH of the system. If your system KH rises to 10, then you might raise the reactor pH set point to 6.6, which means less CO2 goes into the reactor, dissolving less media and releasing less bicarbonates, thereby lowering the KH of the system.
Flow rate (effluent rate) and bubble rate can be adjusted, but the ranges I gave for those should work for most systems. I have just found it easier to mess with one parameter at a time, and reactor set point works the best, IME. Also it is better for someone new to calcium reactors to only play with one variable until you get some experience.
But definitely know what happens chemically to your reactor, the media, and your water column in general before setting up and starting operation of a calcium reactor.
Your reactor media dissolves very slowly, and generally you should not have to refill for a couple years, or until you deplete half the media. A lot really depends on the demand of your system. SPS systems show small demand whey you have tiny frags, of course, and demand increases as they grow. Far less demand from an LPS dominant system, IME.
Main thing IME is to monitor KH, as calcium and magnesium levels usually fall in line at a properly maintained in range KH level. I keep mine at 9, with a general range of 7-12 bring the range recommended by Randy Holmes Farley. The middle of that seems a good place to be.
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. I still go back to that thread reading all the posts piece by piece whenever I have down time. Just so much information packed in there. I think once I start getting it going then some of the discussions will become more relevant to me then.
