So, i did this. Instead of dosing an amount i calculated to add 1mg/l seperated into 3 additions per hand directly into the intake of a surface skimmer every day (which i have done since july), I added an amount that i calculated to amount to the same addition based on my current alkalinity consumption to my sodiumm carbonate solution.
Now i see that my tank has an abysmally low magnesium concentration at around 1170 mg/l, down from 1370mg/l around when i started this thread, so a few weeks ago. I checked the test against two reference solutions and it reads about 50-70 mg/l high rather than low.
My calcium and alkalinity were also very low at the same time (was away from home for a bit more than a week) and corals do seem to have had a bit of a growth spurt from what i can tell. Now i can't really tell whether i just had this growth pulling all my values down, but i kinda doubt it since i never really had to dose magnesium, i still have the same 500ml bottle i got mostly full from the previous owner of the tank years ago.
The other option being that a bunch of magnesium hydroxide precipitated and never redissolved for some reason leading to calcium carbonate precipitation. The dosing tubes are located at the outlet of a hangon filter, the sodium carbonate solution is dosed dropwise 24 times per day and has always produced a white cloud that dissipated within seconds. And it didn't really get any whiter or take longer to dissipate after the addition of the sodium silicate to the carbonate solution.
Is it just the difference between relatively high flow and extremely high flow at the point of addition that broke my neck here? I would have thought that dosing 24 times a day instead of 3 would make up for that.
