JeF4y
09/30/2009, 12:36 PM
(Preface - I've read Melev's CA reactor setup article a dozen times, as well as the reefkeeping article and a few more.)
We recently picked up a used calcium reactor and are putting it on our 60 cube with 20g sump (total water volume after displacement should be around 60G). Right now we have a pretty light load of corals and no clams, but are intending to add a clam within the near future. The tank itself consumes very little CA, but the Alk does tend to drop a bit and maintaining a decent pH (above 7.8) has been challenging at times (we're now in the 8.1 - 8.2 range)
Since the reactor is second hand, there is no documentation, but honestly, I don't know that it really matters since the hardware is irrelevant, but the science behind it is the key guide.
We have the setup as follows:
CO2 provided via bottle with solenoid control, managed by a reef controller (neptune apex)
pH monitored in main reactor chamber via a (new & calibrated) pH probe into the Apex controller.
Secondary reactor chamber holding smaller ARM media to help gas off remaining CO2 before the effluent drips into our sump, right at the skimmer where any final remaining CO2 can be gassed off through the skimmer bubbles so as to not lower our pH in an already pH challenged tank.
In our first tests, I set the pH of the main reactor chamber to be 6.5 - 6.9. As in, CO2 would pop on when the pH increased to 6.9 and stay on until that pH dropped to 6.5.
I did set the bubble count around 1/sec for CO2 but it's difficult to get lower than this due to the regulator control.
We also ran the effluent at 50mL/min.
THIS BRINGS UP MY MAIN QUESTION
What difference does bubble count make if you are using a reef controller with a pH probe? Isn't the goal of the bubble count to simply keep the pH in the reactor at a set level? If I do that via a reef controller that controls the pH within a certain range (6.5 - 6.9) is bubble count a concern at all??? Yes, I understand that if I open up the effluent flow high enough I would have to increase the CO2 supply to be able to keep up with it, but my thought is that the only 2 adjustments that I have that make sense are either effluent drip/flow rate or pH level in the reactor.
The reason I have this question is that in our first few days we've had issues with the Alk climbing too high (ultimately went to 16). We shut off the CO2 just to bring things back down and develop a gameplan and it has dropped to 13 overnight. I suspect we could be ready to begin running CO2 again within the next day.
So given that the Alk of the tank is increasing too much, as I see it I have a few choices.
1. Raise pH level of the reactor up. Thinking of going like 6.8 - 7.2, but using ARM media, I'm not sure if it will actually dissolve anything if I go above 7.0.
2. Increase effluent flow. Increasing the effluent flow SHOULD in theory drop my alkalinity because it has less time to dissolve media. However, my thought on this is that it will also increase the pH of the reactor itself, thus requiring more CO2 to maintain the 6.5 - 6.9 pH I desire. So what sense does that make?
3. Alternatively, if I were to slow down the effluent significantly, (like to say 5ml/min) I would think it would be pretty concentrated in ALK/CA, but the lower amounts being introduced into the tank should have less of an impact on the ALK in the tank as a whole.
So... if you've digested all this, do you have any recommendations for:
pH levels in the reactor chamber
bubble count relevance when using a controller & solenoid
effluent drip rate
Thank you in advance..
-Jeff
We recently picked up a used calcium reactor and are putting it on our 60 cube with 20g sump (total water volume after displacement should be around 60G). Right now we have a pretty light load of corals and no clams, but are intending to add a clam within the near future. The tank itself consumes very little CA, but the Alk does tend to drop a bit and maintaining a decent pH (above 7.8) has been challenging at times (we're now in the 8.1 - 8.2 range)
Since the reactor is second hand, there is no documentation, but honestly, I don't know that it really matters since the hardware is irrelevant, but the science behind it is the key guide.
We have the setup as follows:
CO2 provided via bottle with solenoid control, managed by a reef controller (neptune apex)
pH monitored in main reactor chamber via a (new & calibrated) pH probe into the Apex controller.
Secondary reactor chamber holding smaller ARM media to help gas off remaining CO2 before the effluent drips into our sump, right at the skimmer where any final remaining CO2 can be gassed off through the skimmer bubbles so as to not lower our pH in an already pH challenged tank.
In our first tests, I set the pH of the main reactor chamber to be 6.5 - 6.9. As in, CO2 would pop on when the pH increased to 6.9 and stay on until that pH dropped to 6.5.
I did set the bubble count around 1/sec for CO2 but it's difficult to get lower than this due to the regulator control.
We also ran the effluent at 50mL/min.
THIS BRINGS UP MY MAIN QUESTION
What difference does bubble count make if you are using a reef controller with a pH probe? Isn't the goal of the bubble count to simply keep the pH in the reactor at a set level? If I do that via a reef controller that controls the pH within a certain range (6.5 - 6.9) is bubble count a concern at all??? Yes, I understand that if I open up the effluent flow high enough I would have to increase the CO2 supply to be able to keep up with it, but my thought is that the only 2 adjustments that I have that make sense are either effluent drip/flow rate or pH level in the reactor.
The reason I have this question is that in our first few days we've had issues with the Alk climbing too high (ultimately went to 16). We shut off the CO2 just to bring things back down and develop a gameplan and it has dropped to 13 overnight. I suspect we could be ready to begin running CO2 again within the next day.
So given that the Alk of the tank is increasing too much, as I see it I have a few choices.
1. Raise pH level of the reactor up. Thinking of going like 6.8 - 7.2, but using ARM media, I'm not sure if it will actually dissolve anything if I go above 7.0.
2. Increase effluent flow. Increasing the effluent flow SHOULD in theory drop my alkalinity because it has less time to dissolve media. However, my thought on this is that it will also increase the pH of the reactor itself, thus requiring more CO2 to maintain the 6.5 - 6.9 pH I desire. So what sense does that make?
3. Alternatively, if I were to slow down the effluent significantly, (like to say 5ml/min) I would think it would be pretty concentrated in ALK/CA, but the lower amounts being introduced into the tank should have less of an impact on the ALK in the tank as a whole.
So... if you've digested all this, do you have any recommendations for:
pH levels in the reactor chamber
bubble count relevance when using a controller & solenoid
effluent drip rate
Thank you in advance..
-Jeff