they do tell you it should be in a low waterflow area in you tank(i use the small block one or two at a time, last about 2 to 4 days) i do beleave there is a lot of flow in a sump so it arodes, not disolves. i have to ask what the paramiters went to after that happened?
i have had a black sun polyp colony fall on a candy cane and that candy cane is no more. i beleive a milli knocked out 3/4 of a chalice:eek: