Kan det komma ifrån maten? Har du ändrat vad du matar med nyligen?
Här finns lite att läsa om jod https://reefs.com/magazine/chemistry-and-the-aquarium-iodine-in-marine-aquaria-part-i/
Tänker främst på detta stycke i all text i den artikeln:
"In one study, Gracilaria sp. was found to contain 3654 ppm iodine by dry weight.27 So the daily input to a tank adding 3 grams (dry weight) of Gracilaria sp. per day is about 11 mg of iodine. That is enough to bring a 50-gallon tank from zero to natural levels (0.06 ppm iodine) EVERY DAY. In the end, I think that we should be very happy that iodine is depleted so rapidly, because if it were not, we’d probably rapidly drive up iodine levels in many tanks."