what would cause alk swing when using a cal reactor

[ReefCycle]

I regularly test
water parems, varying at diff times a day. and I am always at same levels. my tank and corals are doing well, I just was reading and everyone was saying they had swings and had a hard time dialing in. I guess my apex solved that problem for me. I also have a massive amount of water volume. Besides doing water changes weekly and my reactor, I don't do anything else. when would alk swings happen? So I could double check and test parems then.

 

[mike007]

Usualy at night after the lights have been off ph and alk. will drop some.

 

[ReefCycle]

oo ok, I knew the ph and alk was related, and my ph stays from 8.25-8.30 all day and night. I knew about reverse ph swings, I just thought that with calcium reactor specifically caused alk swings when I have never tested and found this to be true. But the people who reported it were also the ones referring to calcium reactor dialed in

 

[rossco]

Alk swings can be either caused by equipment failure or as in the cause of my big alk drop and subsequent recession event, by getting too comfortable with the stability, not paying attention and running out of CO2. In a SPS heavy tank like mine, the alk can drop to lethal levels in a few days if the reactor goes offline.

Other than that, quite often if reactor system is taken apart to add media or even change the CO2 tank it can cause swings either up or down and the output has to be re-tuned to match consumption. I now visually check the effluent rate, CO2 pressure and reactor pH much more frequently and try to test at least once a week.

Using the Apex to run the reactor will work, but it is best to get the CO2 and effluent rate pretty close to perfect without having the Apex turn it off and on a lot just to safeguard against equipment failure such as the ph probe, solenoid, or even the controller itself.