Calcium Reactor Primer: Theory and Fine Tuning
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?... the primer says Mls per minute?
Grant,
At the settings you have, you should not have any issues with the pH of the reactor getting to a 6.6 or lower setting. MRC recommends using fine media, so you are good there as well. The CR2 is a dual chamber reactor, correct, with a reactor chamber and a passive 2nd chamber to pass the effluent through prior to it going back into the sump? And your recirculation pump is working? The top of the reactor has a pH probe port I assume, so the probe is inside the reactor water and you are not measuring effluent output in the sump, right? And I assume both your reactor chambers are filled with media?
What kind of controller are you using, and is your probe calibrated? If I were to guess based on your information, I would guess that your probe needs to be calibrated or is defective. Because at a bubble count of 60-90/minute and effluent rate of 50-60 ml/minute, your reactor should be regularly coming on and going off. It should have no issues getting to a 6.6 setpoint.
Your rector is a fine size for your system, and shouldn't have issues keeping up with your tank's ca, mag and KH demands.
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Hey Dave!
Your assumptions about the reactor are correct. I have the second chamber roughly half to two thirds full of media. I'm controlling it with my apex unit through a pm1 unit. The pH probe was new and I calibrated it a few weeks ago. I suppose it needs it again? If I turn off the co2 the ph in the reactor will approximate the display pH reading after a few hours.
Your assumptions about the reactor are correct. I have the second chamber roughly half to two thirds full of media. I'm controlling it with my apex unit through a pm1 unit. The pH probe was new and I calibrated it a few weeks ago. I suppose it needs it again? If I turn off the co2 the ph in the reactor will approximate the display pH reading after a few hours.
I would calibrate the probe/controller and report back. You really do not calibrate probes. The popular jargon is to "calibrate the probe." You actually calibrate controllers to the functioning of the probe, which is done thru the pH 7 and 10 solutions.
You pH probe sits inside the reactor thru a probe port, right? These are an option on MRC reactors.
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I'll puck up some calibration fluids this weekend and recalibrate the probe to see what effect there is. I had MRC install the probe holder in the lid for me and I have the probe sitting approximate one or two inches into the first chamber.
Thank you for the help!
Thank you for the help!
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Okay... update time:
I was finally able to locate an LFS that had 7.0 calibration solution and recalibrated my pH probe with 4.0 and 7.0. At the same input and output parameters as my original description, I'm still having issues getting the pH to go down.
At ~90 BPM (possibly more... its difficult to count em when there is more than one per second), and 60mls per minute of effluent, my pH is at 6.69 right now and ranges between 6.68 and 7.02.
Tested a day after and my Alk was at 3.5 meqs. Calcium is ~375.
I should note that I can tell myrecirc pump is working, but I can see air or gas building up at the top of the reactor chambers?!
I was finally able to locate an LFS that had 7.0 calibration solution and recalibrated my pH probe with 4.0 and 7.0. At the same input and output parameters as my original description, I'm still having issues getting the pH to go down.
At ~90 BPM (possibly more... its difficult to count em when there is more than one per second), and 60mls per minute of effluent, my pH is at 6.69 right now and ranges between 6.68 and 7.02.
Tested a day after and my Alk was at 3.5 meqs. Calcium is ~375.
I should note that I can tell myrecirc pump is working, but I can see air or gas building up at the top of the reactor chambers?!
This one is a head scratcher for me. You should not have any issues getting your reactor below 6.69 with the bubble count/effluent rate you are using. And if you see gas collecting at the top of the reactor chamber, then you are bubbling CO2 too fast. Cut it back to 70-80 bpm. You are putting CO2 in the reactor faster than it can dissolve. I suspect you may have a bad pH probe. You can check this.
Do you have an in-tank pH probe? Here is what I would do next. Stop your reactor feed pump, recirculation pump, and unplug the CO2 solenoid. Remove the pH probe from the reactor, and place the reactor pH probe in the sump and see if it agrees with your system pH monitor. Assuming it is good, it should be in close agreement with the tank probe. If it is showing a very different reading than the tank probe, then you probably need to replace it or it is defective.....and I know you said it was new, but over the years I have had my share of defective "new" probes bought straight from the manufacturer, particularly when the liquid the probe tip is supposed to be in has dried out prior to my purchasing it.
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Hmmm well... I'll add to the head scratching. The calcium reactor probe reads 8.12 in the sump... The display tank probe reads 8.19. Different, but only by .07. Is that enough to say the probe is done? Could this be a regulator issue?! (I highly doubt this since I can control the bubble rate).
Sounds like your probe is OK. That difference is not significant enough to say the probe is bad. Your display pH is fine, same as mine a lot of times
Regulators tend to either work or not work. You are probably fine there as well.
Your calcium reactor is pulling the pH down somewhat, but not as much as it should. That is the part I don't understand.
I may need to make a house call on this one!
I am out of reasons for it not going to where it should go. You should have the ability to take that reactor pH down to 6 or less.I'd be happy to come take a look if you like. Send me a PM.
50-60ml/minute is the recommended starting flow rate for MRC and GEO reactors. If the pH in the reactor doesn't drop if he lowers the rate below that, then there is something really wrong. My point is, Grant shouldn't have to lower it below the rate of 50-60 ml/minuted to reach his controller setpoint.
The above is assuming he has collected the effluent for one minute and the volume is 50-60 ml. Eyeballing it is not the best way.
The above is assuming he has collected the effluent for one minute and the volume is 50-60 ml. Eyeballing it is not the best way.
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Hey Dave,
THAT would be awesome on a number of levels... be warned... I'll try to pick your brain on a number of different topics!
I'm actually going to be out of town for a few days so we can work something out. I'll shoot you a PM. Thats an incredible gesture.
As for collecting the effluent, I basically took one of the measuring cups I got with my BRS two part setup and collected for a minute. The valve is definitely touchy. I can barely squeeze the valve and the effluent will go up or down depending on which direction I'm pushing obviously. Right now its sitting at ~65mls/minute. It had dropped down to 30mls/minute?
As we sit right now, my Apex is telling me that the pH in the reactor is 6.62, but this is still with the high bubble rate.
One more thing, the air that is in the top of the chambers remains from when I turned the feed pump off and the water level came down. Since the water bubble sits above the outlet fitting... its trapped.
THAT would be awesome on a number of levels... be warned... I'll try to pick your brain on a number of different topics!
I'm actually going to be out of town for a few days so we can work something out. I'll shoot you a PM. Thats an incredible gesture.
As for collecting the effluent, I basically took one of the measuring cups I got with my BRS two part setup and collected for a minute. The valve is definitely touchy. I can barely squeeze the valve and the effluent will go up or down depending on which direction I'm pushing obviously. Right now its sitting at ~65mls/minute. It had dropped down to 30mls/minute?
As we sit right now, my Apex is telling me that the pH in the reactor is 6.62, but this is still with the high bubble rate.
One more thing, the air that is in the top of the chambers remains from when I turned the feed pump off and the water level came down. Since the water bubble sits above the outlet fitting... its trapped.
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Apex is set to Low 6.60 and High 6.65. CO2 is on continuously. Given the control I imagine that works out to a setpoint of 6.60 with a hysteresis of 0.05.
Your setpoint is midway between the high and low. The hysteresis goes the same increment above and below the setpoint. So if your high point is 6.8 (CO2 turns on) and your low point is 6.6 (CO2 tuns off), then the controller setpoint is 6.7 with a hysteresis of .1 (above and below the setpoint).
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Hmmm... all the Apex asks for is the high, the low and then whether I want the outlet on when the value is at the high or the low... I have it set to be on when the value is high.
I see...your Apex has you program the high and low point, and the controller setpoint is midway between those values. The hysteresis is the equal amount above or below the midway point (controller setpoint).
My RKE has me program the controller setpoint (midway point) and the hysteresis, then the RKE turns the CO2 on/off at the high or low point.
2 different ways of doing the same thing.
