I'm curious to collect some info from those people who see potassium depletion in their aquaria. I've never really been convinced that potassium should deplete based on coral usage, and yet it is the people with a lot of hard corals that seem to see it and dose it.
Now it occurs to me that people using a two part that does not have enough potassium in it may see depletion simply due to the increase in salinity from the two part, which, when lowered back to normal salinity, will effectively look like potassium depletion.
In fact, someone who doses the equivalent of 4 dKH of alkalinity per day using a two part with no potassium will, over the course of a year, drop potassium quite a lot. Assuming you readjust salinity every day, it drops from 400 ppm to 237 ppm. Half that amount of two part will drop potassium by half as much, to 319 ppm. And finally, someone adding only 0.37 dKH per day will drop potassium from 400 ppm to 367 ppm.
This all assumes no water changes and imports from foods and such exactly matching consumption (which it might roughly do, depending on the system).
So to the poll. I cannot know whether commercial two parts add sufficient potassium, but I suspect that DIY two parts that do not use the Dowflake I originally tested (which has adequate potassium in it) may be adding too little potassium in some cases if they are now using more purified calcium chloride materials.
What have you observed?
Now it occurs to me that people using a two part that does not have enough potassium in it may see depletion simply due to the increase in salinity from the two part, which, when lowered back to normal salinity, will effectively look like potassium depletion.
In fact, someone who doses the equivalent of 4 dKH of alkalinity per day using a two part with no potassium will, over the course of a year, drop potassium quite a lot. Assuming you readjust salinity every day, it drops from 400 ppm to 237 ppm. Half that amount of two part will drop potassium by half as much, to 319 ppm. And finally, someone adding only 0.37 dKH per day will drop potassium from 400 ppm to 367 ppm.
This all assumes no water changes and imports from foods and such exactly matching consumption (which it might roughly do, depending on the system).
So to the poll. I cannot know whether commercial two parts add sufficient potassium, but I suspect that DIY two parts that do not use the Dowflake I originally tested (which has adequate potassium in it) may be adding too little potassium in some cases if they are now using more purified calcium chloride materials.
What have you observed?
