I have usually used the copper product from Aquarium Systems.
I don't think it's chelated. Some of thse products are harder to measure/test for levels. Keep in mind, this need not be the end of the world... agree no substrate is best (it binds the copper) but if you cannot remove it before treatment, simply replace it later in portions.
The only thing I would clarify about the previous posts from others would be number 5. "replace all filter media, substrates, and sponges etc if you have any." IMO, you would want to REMOVE any chemical media during treatment, (not replace it) you can add a Polyfilter pad later to remove the copper but that would not be advisable, as I said before, you may want to maintain a certain level for new arrivals. With 70 fish, do not replace your bio filter media; even though the copper will put a dent in your bacteria it will not kill all... your system will rebound. Keep a watchful eye for Ammonia during treatment and several weeks after, water changes as needed.
I don't think it's chelated. Some of thse products are harder to measure/test for levels. Keep in mind, this need not be the end of the world... agree no substrate is best (it binds the copper) but if you cannot remove it before treatment, simply replace it later in portions.
The only thing I would clarify about the previous posts from others would be number 5. "replace all filter media, substrates, and sponges etc if you have any." IMO, you would want to REMOVE any chemical media during treatment, (not replace it) you can add a Polyfilter pad later to remove the copper but that would not be advisable, as I said before, you may want to maintain a certain level for new arrivals. With 70 fish, do not replace your bio filter media; even though the copper will put a dent in your bacteria it will not kill all... your system will rebound. Keep a watchful eye for Ammonia during treatment and several weeks after, water changes as needed.