CalhounReef;998851 wrote: Dave, about how often do you have to mess with/adjust the reactor on the big tank, and how much media is that burning through if you don't mind?
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 rIse 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 somet 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.
Edit: Raj states servicing the reactor ever 6 months. Your mileage may vary with this. I go much longer thank Raj does, but I also dose Kalk, which probably decreases the rate I dissolve reactor media.
