[Henry Bowman]

First thing, take a Ca and Alk reading from the tank asap...test water should be nowhere near the Ca reactor. preferrably take the reading out of the actual tank....

Your reactor is barely putting anything into the tank running a pH of 7.2

Until the pH of the effluent reaches the high to mid 6's (ie 6.6-6.7) you are not adding much Ca or alk to the tank. It appears from your readings that when you upped the bpm to 10 and the pH in the effluent dropped, and Alk jumped, you started to a little bit of the media.

Now, you need to start taking daily reading of the TANK. Leave the reactor alone since it sounds that it is slowly releasing some Ca and Alk. Many reactors run an effluent pH of 6.5 (dont go lower it will turn the reactor media to mush) and an effluent alk of 15 or higher.

Need to know what is happening in the water column (the tank itself) over say a 2-3 day period with readings taken daily (again, from the tank). With the reactor running steady, you should be able to see if the tank's reading is changing daily. With alot of corraline and other corals in there, you will probably see the reading going down a little day by day. If your target Ca is 420 and at the end of the 2nd day it has dropped to 390, increase the BPM of the reactor to about 15. AND add a calcium supplement to bring the actual Ca in the tank up to 420. ...... Check the Ca a day or so later, and you'll probably find that the Ca has dropped less than before. This time it may have only dropped to 410. This is due to the reactors output coming very close to what the tank's conusmption is. Again, you are going to add some Ca supplement to get the Ca back up to 420 and adjust the reactor.

All along you need to check the pH of the reactor effluent. IF the pH reaches 6.5 and the reactor is still not keeping up, you will have to increase the effluent drip rate AND increase the Co2 BPM to bump up the production of the reactor.

This basic cycle will continue of testing and adjusting until the tank holds a steady Ca at your target (my example was 420 ppm). Since the reactor adds Ca and Alk in a balanced manner, once your Ca is in line, your alk should be fine too.

HTH