I disagree if your treating ick for a FO
tank. Copper is a very effective method of treating ick. Of course you need to consider the brand of copper. Over the past 25 yrs of keeping marine FO
tanks, I've never had a disaster from dosing with copper. I do recommend Seachem's Cupramine over any other brand though. Copper is a lethal substance, but it also seems that Cupramine is in a less lethal formulation. Copper will be absorbed by your dead coral decorations and your crushed coral substrate so to have a correct ppm
, you do need to test for concentration when treating for the copper to be effective. You also need to turn off any skimmers, UVs, ozonizers and remove your carbon. Once your treatment is over, you can turn on these equipment, perform a water change and add new carbon and the copper levels will be almost undetectable. (well undetectable with a copper test kit, but we all know that the dead coral & substrate will have absorbed some of this copper)
As with Hypo-salinity, in my experience, you need to bring the salinity all the way down to 1.010 SG
for this to be theraputic. You need at least 7 days to bring this down from 1.024 SG
( no more than .002 per day). If you have a outbreak and did not catch it from the beginning, then 7 days might be too late. I've had success also with hypo-salinity, but I've also had a outbreak @ 1.014 SG
If you have any inverts or live rock, then none of these options are for you.