reef211:
Are you using a CO2 controller and if so how is it set up?
If your set point is 6.5 but the reactor go as low as 6.0 you may have the controller set up inverted. The way to set up the controller is to have it cut off the CO2 while the PH in the reactor is dropping but some controller can be set up either way and cut the CO2 when the PH in the reactor is going up which for a calcium reactor is wrong.
In the wrong mode the CO2 will say turn on at6.5 but because the CO2 drops the PH, the PH will continue dropping and the CO2 will never shut off.
In the right mode as the PH drops (say from 6.7) once the PH reaches the set point (say 6.5). Once the PH reaches 6.5 the CO2 turns off so the PH starts to rise. Once the PH reaches the higher limit in the controller (say back to 6.7) he CO2 will turn on again and repeat the cycle.
A couple of tips:
a) As mentioned above in the posts, although possible, you should not try to increase neither the Calcium nor the alkalinity using the reactor. The reactor will add 20 ppm of calcium for every 2.8 dKh of alkalinity.
Say if you try to increase the calcium from 360 to 420 ppm, your alkalinity will shoot by an additional 8.4 dKh, if your present alkalinity is at say 8 dKh it will rise to more than 16!
If you adjust your reactor to increase the levels you will probably overshoot and make re-adjusting very difficult.
b) Adjust the reactor to maintain constant alkalinity, once the alkalinity is maintained (regardless of the level) your reactor is at the right set point point were your alkalinity consumption equals the alkalinity added by the reactor. Once there, use manual supplementation of calcium chloride (Turbo Calcium, ESV Cal chloride, Dow flake etc) and baking soda to adjust the levels were you want them and the reactor will keep them there.
c) The easier way to adjust the reactor by trial and error is to set an starting effluent level of say 40 ml/min and adjust the controller (and bubble rate so a start up PH (say 6.7. Test your tank alkalinity in 24 hour periods. If the alkalinity is dropping then reduce the PH y 0.1 units at a time until the alkalinity stops dropping or you reach 6.4
If you reach 6.4, increase the effluent flow by 50% and start again with a higher PH and lowering it again until the alkalinity is stable.
If in the process your alkalinity drops too much (Less than 8 dKh) you can add some baking soda, wait 2 hours, test the reading after the addition and keep going with the process.
Good Luck!
