For future reference, copper and hyposalinity should never be done in your DT. As Kurt said, the rock can and will absorb an undetermined amount of the copper out of the water column. Further more, copper treatments kill the beneficial bacteria needed for the nitrogen cycle leaving your fish exposed to dangerous levels of ammonia and nitrites and it also essentially turns your LR
into dead rock. Also, now that the rock has absorbed copper, after you stop treating it, copper will be present in your tank indefinitely as it leaches back out of the rock.
That is why a QT tank is crucial to have for dosing copper or doing Hypo. It allows you to consistently monitor the copper levels with out worrying about the rate at which the LR
is absorbing it and it also makes it easier to keep the amm/nitirite levels in check with water changes. Ideally when dosing copper, a 10-20% water change twice a day will keep the levels in check and help keep the water in pristine condition for optimal recovery.