Here's my take, based on my own experiences and studies, and as shared with other aquarists:

My treatment of preference for Amyloodinium and Cryptocaryon irritans:

First off, it must be in a FO tank, just FO, No liverock, livesand, etc. All bio systems intact, with the elimination of carbon, if being used, or any other chemical media. All other filter media (biological) is not adversely affected IME. If Protein Skimming is being utilized, it must be discontinued for the duration of treatment (4 weeks). When using copper treatment in a Q tank, special emphasis needs to be placed on having a mature and completely cycled bio-filter.

In my earlier days, I was skeptical about bio-filteration affects using chelated copper, so I also carefully monitored ammonia and nitrite, as well as nitrate, during treatment. IME's, no measurable changes were detected. First off, its very important to know, VERY CLOSELY, the exact volume of water in your aquarium. You must take into account, net internal measurements, plus displacement by substrate, rockwork, appliances, plus, what might be added by sumps, canisters, etc. Accurate dosage is essential, so actual volume can be critical.

Based on this, I have consistently employed CopperSafe� from Mardel Labs�, as my choice of treatment. It consists of dosing, at the precise recommended amounts, by the manufs. dosage size, to as close to the exact net volume of water being treated. Once that is done, copper levels are tested by a Kordon� Chelated Copper test kit (two part dry powder method) until copper levels reach 2.5ppm, as indicated by comparing test water with a color standard. This should be done within the first 4 hours of treatment. When treating species known to be more sensitive to copper, as some species of Butterflyfish (almost all), Angels (a few) and Tangs (also a few) Initial copper level is allowed to go down to 2.0ppm, but not below for maximum effectiveness.

Monitoring is also done daily, for the full treatment period, which is 4 weeks. In my experience, raising temps, which accelerates the life cycle time of the parasite, which is a treatment option in FW, is not recommended with SW, with its decreased and limited oxygen levels. All basic systems are left, as usual, feeding, lighting, temp., bio- filtration (with the exceptions as above). pH and nitrate is also monitored.

Its very important NOT to place any additional stress on your fish. Following those 4 weeks, a 25% water change is recommended, and an additional 25% water change, the following week.

Following this 6 week regimen, all should go back to normal schedules for water changes, etc.

Copper will dissipate, by adsorption with calcium carbonates, but can be accelerated by the addition of activated carbon or a poly filter. Generally speaking no detectible copper levels will show up after 8 weeks, following initial dosage, although in some cases, a very slight level might be detected.

Unfortunately, one adverse effect of all copper treatments, is the demise of almost all algae growth. IME's, once copper levels dissipate, algae growth does resume. Following copper treatment of any type, its virtually impossible to introduce any invertebrate life forms without replacing all substrate materials, rockwork and bio media, which all harbor and leach small, but lethal amounts of copper (for invertebrates) for a considerable length of time.

During treatment, at no time is the copper level allowed to go below 2.0ppm. Some experimental and additional dosage is required, because, although claims are made as to chelated copper's ability to remain in solution in the presence of calcites and carbonates, adsorption still occurs. Careful monitoring is essential, and many failures utilizing chelated coppers, can be laid to the absence of careful monitoring.

One must always remember that copper is highly toxic, can irritate the fish's breathing mechanism (gill tissues), be ingested, and causing organ and brain damage. DO NOT OVERDOSE! Some cases are more stubborn then others, so greater patience must be exercised.

In dealing with certain fish species that have shown an increased sensitivity to copper (its also an essential prerequisite to be familiar with the biological and adaptive mechanisms of your fish), this might not be the best method of treatment.

In many cases, treatment with hyposalinity, might be the first treatment of choice, where applicable. One of the biggest obstacles in utilizing hyposalinity in an established tank, is the almost catastrophic effect it has on bio-filteration, especially on denitrificating organisms and constant (12hour) testing is essential to detect any rising ammonia levels. Hyposalinity is only recommended in a separate aquarium.

Its also very important to understand the complex life cycle of many parasitic protozoans, and other parasites. Because of these factors, greater effort needs to be expended in their erradication, as many 'radical' or 'new-age' methodologies only results in continuing infections, and when fish are 'stressed', re-occurances are almost guaranteed.

Symptom management is simply not enough. This has led to the widespread erroneous belief that C. irritans, is always present, in an otherwise healthy tank. What has occured, is that, a very low level of infection, undetected, has been in the tank all along.

Unfortunately, there are no easy answers and one can expect a certain number of mortalities, as one travels down this road of experience, failure and hopefully, triumph.