calcium reactor J chamberCalcium Reactor Modification Part 2

by Justin Hester

A few weeks ago we had done a little experiment to try and raise the pH of our calcium reactor effluent before it returned to the tank.  This week, we took it to a whole new level and got some immediate results!

In the past, we’ve seen “extra chamber”  modules sold for people to add to their calcium reactors in order to give a bit of relief from the low pH.  These chambers basically added a new area for the low pH water to react with and further dissolve aragonite before returning to the tank.  This dissolving has a net raising of the pH and in the case of these chambers, was done primarily in the absence of oxygen.  This was nice, but it only took the pH say from 6.5 in the main calcium reactor, to about 6.7 after the second chamber.  Putting this 6.7 pH water back in your tank usually meant it would lower your tank pH too which wasn’t a good thing.  In a tank like ours, the shear amount of this low pH effluent forced us to take other measures to keep our tank pH from swinging from 7.8 at night to 8.2 during the day.  A swing like this is way too much and was starting to cause signs of stress in our corals.  This is what prompted us to come up with what we call the J Chamber.

How to make a J chamber


About a month ago, I got an idea.  What if having your calcium reactor drip through column of aragonite would help boost pH while preserving alkalinity?

Could we effectively raise the pH of the return effluent withOUT affecting the dissolved carbonate and resulting alkalinity we were trying to return to our tanks?  In short, by trickling water down the J chamber and then bubbling an air stone in the bottom of the J, we were able to return the water to our system almost back at a pH of 8.

We did this by taking a 3ft piece of 3″ PVC and added a trap U fitting on the bottom.  We then attached this to our tank stand in our sump, fastened with a pipe hanger turned sideways.  Before filling the column with aragonite or dead coral skeletons, we put an air stone in the bottom which is then held in place when the aragonite is filled.

Today we will be testing the alkalinity of the effluent from the reactor as well as that of the effluent after the J chamber to see if we are losing some alkalinity as carbonate.

Stay tuned for an update!