Hypo-salinity Treatment levels are 1.009, not 1.016, so you are really doing disease suppression at that level. Same with lower dosage of Copper. Good retail strategy to keep the fish alive and remove active issues but it is not eradicating disease, just suppressing it. Observing a fish for disease while under active disease suppression will just cloak the presence of infection/disease. These are effective retail strategies, but could be considered misleading to a customer if you are stating these are Quarantined fish.
Hyposalinity aka Osmotic Shock Therapy (updated 1-11-23) What It Treats: Marine Ich (Cryptocaryon irritans) and Flukes (Monogeneans) How To Treat: Place the fish you wish to treat in a quarantine tank with SG & temperature matching the tank they came from. Over a period of 48 hours, gradually...
humble.fish
How to Setup a Quarantine Tank (updated 4-6-2023) The following are the essentials: Aquarium (10-30 gallons seems to work for most people. A larger QT lets you house more fish and gives you more wiggle room when it comes to ammonia. A smaller QT is cheaper, easier to maintain and can be...
humble.fish
I think what you are doing is perfect as long as you don't label the fish as Quarantined. If you really want to market fish as Quarantined, you should spend some time at Humblefish to develop a protocol that will work with you and your store and decide on what diseases you want to treat for and do it right. It will 3x the cost of the fish. You also need to hold the fish for a while so their immune system gets a chance to recover. That takes a lot of time, space and energy. I personally feel a LFS doing observation and removing sick fish before they get in your retail tanks like you are doing is the best you can do as it protects your fish system and gives customers some assurance that the fish is healthy enough to take home and QT as they see appropriate. I would rather see the observation period be done while not under disease suppression, but I understand while it isn't being done that way.