Cryptocaryon irritans.
Like many we’ve lost a few fish to this parasite. We started to control this by using Ozone but due to severe headaches and feeling sickly even though I was dosing the recommended levels, using a controller, running through carbon etc a slight odour was still present and strangely only affecting myself. You will recall the other five footer we bought to re house the Malawi's, this was now sitting empty as we were now strictly salties only even though things were not looking good. I found myself starting to spend a lot of time in the Fish Health section on Ultimate Reef and do honestly regret I even went there. There is good advice from members who have quarantined their livestock from day one and had 100% success but for us it was disastrous, we lost more fish during quarantine even though I was following top advice from Ian (Wombat) using copper and a test kit. Of all the fish that died (or should I say poisoned) I lost a yellow tang I’d had for a while. She had been through numerous battles to this parasite. Among others we also lost one of our clownfish that died due to taking skin scrapings etc. The clown died because copper treatment wasn't working so we tried Hyposalinity at 1.009. It was suggested to do a skin scrape and take a look under the microscope. On doing the skin scrape this removed some of the protective muscus from the fish. On returning the fish to the tank too much water was taking in and the fish drowned.
I had remembered reading an article about a fish's internal Osmolarity which is 1.012 during my research on C.Irritans.
My mind was that full off numerous articles I had read and I was completely stressed out with all that was happening I simply forgot, losing the clown was the final straw. The remaining fish were returned to the display a TMC 30W UV was fitted and the tank left alone.
Since then I will never regret moving the remainders to the display, some may think it is ignorance or stupidity but for us it worked and continues to do so today. Since all fish were returned to the display last year we have added another eighteen fish since January this year with no losses or parasite infections, all fish look pristine with crystal clear eyes. Obviously not top advice but the quarantine period was just too much for us, I would say for myself more, probably because I was more involved than my Mrs with the tasks in mind, I don't feel bad about anything when I look back as I believe I tried my best even though I failed, I think it's fair to say for fish quarantine to be fully effective you would have to treat fish for all known parasites, on saying that, the fact will always remain that prevention is better than cure.

Our
Contradictive Quarantine Thread (well there were moments I did believe things were getting better)
Nitrate:
For the first two and half years NO3 levels were 50ppm+ I was doing things I would never have dreamed off if I hadn't been a member on UR like adding sugar, vodka etc I soon stopped after reading & hearing of further problems etc.
I then stumbled over SCOOBs thread
"Nitrate free-fall, 70 to 7 in just 14 days" following his findings I soon found myself making more promises to my Mrs, like "what's the damage? We’ve only got one tank now it won't cost a lot, and it's only two bottles!". Coughing out more cash on Fauna Marin products ie. Ultra Bak & Ultra Bio, I bought quite a few bottles I can tell you but never got anywhere near SCOOBs results even after several months. I think I managed to get NO3 to around 25ppm at one time.
I did however find a remedy! Prior to water changes I started to disturb the substrate behind and under the rockwork also at the front of the tank and within a few months NO3 started to fall. Nitrate levels in the tank now sit at zero and I am totally chuffed.