Hello I have a RedSea 750xxl. I started my first tank without quarantine fish and after my fourth round of adding fish some got sick and wiped the tank out. I cleaned out the entire tank and am starting again new. I currently have two clown fish, three small damsels and a tang in a quarantine tank. I got two small 10 gallons. I used the fluval 307 I had from my previous fresh water tank as a filter, added a heater and got some prepackaged salt water. I have the salinity at 1.019, heater around 75-78. I added one packet of general cure a couple days ago along with some Ich medicine. Did water change after 2 days, added api salt to help the fish with stress, again medicated the second packet of general cure and Ich, testes water parameters were good. Did a water change today again after 2 days (only changing around half the water) and only added some Ich medicine to finish the third dose. My tang is not swimming very well. After every water change I add the api salt to help. My one small damsel was dark blue but after the water change and salt turned a light blue shade. Attaching a pic of the QT. Please help me this is my first time doing a QT, I plan to add the carbon back to the Fluval 307 maybe in 2 days to get the medicine out after a day will shift the fish to the other 10 gallons using the same filter and heater but just to make sure there’s no medicine on them before going in the DT. They’ve been in the QT for about a week tomorrow. Any tips or suggestions will be appreciated. My DT I added prepackaged salt water but because it reads at 1.030 I plan on diluting to bring down to 1.020. I have a protein skimmer and heater. I plan on purchasing the marine pure bio spheres for a biological filtration as my DT will be minamilistic, I don’t have any live rock I plan on buying bottles of bacteria to add to the spheres to kickstart the bacteria journey. I’m also thinking of getting a UV light but is there any way of getting one to drop into the sump, I’m not good with plumbing and don’t want to take apart my tank plumbing. I’m also thinking of getting some wavemakers just to better the flow of the tank, I have around 160 gallons in the tank and 40 in the sump, do I need two wavemakers or will one do? Any suggestions on affordable ones? Also do I just put the spheres in or put them in a bag? Any and all help is needed and much appreciated. Literally my first tank and after my last crash I need all the basic help I can get!! Thanks guys!