Glad you got the nack of the test kits
One of the draw backs to B-ionic and other two part liquids is they must be used in unison. If only one of the two is used, the net result will actually be nothing or in fact can supress the element you are trying to raise. It is very important they are used in equal amounts.
I would instead suggest you test a batch of newly prepared SW
after a 24 hr mixing period has passed to determine the levels there. If they are "close enough", do a few more water changes instead. The only alternative to that would be adding a seperate buffer and CaCl
to acheive a reasonable balance later once the chem problems you have now are eliminted.
Right now your concern is allowing the alk
to fall. Since you are in no danger of precip with the Ca
being at 400 ppm
the real concern is the off the chart alk
level. That will honestly fall in the next few days on it's own. Being just shy of 6 mEq/l is not a good level but it should not create a serious problem at the moment as long as you discontinue the additions of the two part liquid for now.
Post back when you have the SW
readings from a new batch.