Post water change parameters:
dKH: 7.8 (this is actually making me think my test kit has gone off, when I tested the batch of water I'm using for water changes when I made it the dKH was closer to 9)
calcium: 405ppm
Magnesium: 1360ppm
Temp: 23.2
Ammonia: undetectable
Nitrite: Undetectable
Nitrate: Didn't test
Phosphate: didn't test
oh I forgot to mention in the last post, SG before and after the water change was exactly 1.025
Here is the tank at 1:58pm, 51 minutes after every coral in this tank was high and dry:
Only the goniopora has yet to fully re-inflate.
I had to go out and pick up furniture right after this, so I didn't get a chance to feed until 7:40, 20 minutes before the lights go out on this tank. I fed a mixture Coral Frenzy and AcansPlus mixed in a dish with 10ml of water so that it formed a relatively thick paste:
I ended up only using about half the syringe, but that's about 1/4 more than I usually ever feed at one time. I also fed the two brains several large pieces of PE mysis.
I usually take gobbling down as much as you can eat as a sign of coral health.
So - if my test kits are to be believed (I'm suspicious of the alkalinity), this water change altered my levels by:
dKH: +1.4
Calcium: +65ppm
Magnesium: +60ppm
Temp: -1.6 degrees
Ammonia: no change
Phos & nitrate: Not sure, but almost certainly drastically lowered them, probably took both down in to the undetectable range.
It doesn't appear to have acutely harmed the corals in any way, as they looked and were behaving completely normally (save for the goniopora) in less than an hour. The stomatella snails in there faired perfectly well, and judging by the number of worms that popped out of the rocks when I started feeding, they didn't seem to mind either.
The next question is whether or not this somehow 'shocked' the bacterial filtration system. I've added a good dump of organic matter that will shortly be converted to waste, so I'm going to test ammonia every day for the next week. I'll post the results here.