Here is an instructional document that I recieved from a VERY experienced reefer on how to set up a Calcium reactor. HTH. :
Here is how I initially set up a Calcium Reactor
First some important tips:
a) Although the reactor adds calcium and alkalinity in a balanced way, their consumption is not balanced, that means that although you set your reactor to maintain their level one of them sooner or later will change. I recommend setting the reactor to maintain constant alkalinity, if the Calcium gets out of balance adjust it using a Calcium supplement (I use Calcium Chloride, Kent's turbo calcium)
b) The amount of alkalinity added by the reactor is controlled by two variables: The amount of effluent flow and the effluent PH
Higher effluent flow at a given PH = Higher addition
Lower effluent PH = Higher addition
(Higher CO2 bubble rate = lower effluent PH)
There are limits to these two variables.
EFFLUENT:
Too high flow the retention (contact) time with the media may not be enough for proper dissolution. Too low of a flow and you will not get the required alkalinity addition. At small flows also is more difficult to maintain the flow steady as the valve may plug or will change the setting with temperature changes. The approximate limits in my experience are: Lower 20 ml/min higher 65 ml/min for small single chamber reactors, 120 ml/min for large double-chambered reactors.
EFFLUENT PH:
Too high a PH the media will not dissolve fast enough, Too lower and the media will get muddy over time, in addition the lower the PH the larger the proportion of carbonic acid to bicarbonate in the effluent so there will be a higher tendency to lower your overall tank PH even if no free CO2 reach the tank.
Range: For easy to dissolve media (like ARM from Caribsea) The lower will be 6.5 and the higher around 7.0, for a harder to dissolve media like Koralith, Gen-X or Schuran media the higher is around 6.8 and the lower around 6.3.
c) Setting up the effluent PH using a test kit will be very difficult if not impossible. An electronic PH meter is strongly recommended although a controller will make life a lot easier.
d) Have a good alkalinity kit at hand as more frequent than usual testing will be required during the setup. I tend to favor kits that read alkalinity in ppm of carbonate, as it is easier to read a change from 160ppm to 175 ppm than a reading from 3.2 to 3.5 meq/lt. which are equivalent.
e) Be very patient: After any change in CO2 bubble rate give at least one or two hours for the PH in the reactor to stabilize before attempting further adjustment. After a set up change wait at least 24 hours (48 better) between tank's alkalinity measures to see if the reactor is coping with the alkalinity consumption.
The whole process may take one or two weeks of trickling before a stable point to maintain alkalinity is achieved. Make small changes and go slow and insure between tests that your effluent rate and PH have been maintained at their desired level.
f) Use CO2 bubble rate as a reference only, the actual important measurement is the effluent's PH level.
A general description of the process I follow is to 1) test alkalinity 2) set up a medium to low effluent rate at a medium to high PH. 3) wait 24 to 48 hours, 4) test alkalinity 5) If higher, lower the effluent and keep PH , if lower, reduce PH and keep effluent. 6) Repeat 1,2,3,4. But his time If alkalinity is higher, increase the PH and keep the effluent , If lower increase effluent rate and keep PH . Keep on repeating these steps alternating adjustments between effluent and PH until the alkalinity remains constant. Once constant alkalinity is achieved adjust to the Alk. and Ca target levels using buffers and supplements.
Test weekly and make small adjustments to the reactor as necessary to keep Alk. constant. Adjust Calcium if necessary using Ca Chloride.
Your starting point can be 35 ml/min and an effluent PH of 6.8 (I think the bubble rate might be at around 40 bpm but adjust it as required to maintain between 6.75 and 6.85
Make effluent adjustments in increments of 10 ml/min and PH adjustments in increments of 0.05
