Ich outbreak and need help

alright i have an issue with ich

i bought a blue hippo tang from a store and it looked great,
when i got it home and under a different type of light, i saw ich all over it but small little white dots not huge massive ones, so i tossed it in my QT and dosed it with "copper power" waited and checked it out then saw that it was getting better about 2 weeks later it looked clean and healthy, so i scooped it and acclimated it to my main display tank.

then about a month later it develops ich spots again, and about 2 weeks later my other fish are starting to get ich, i have since gotten rid of my QT.

i have done searches and found a ton of ways to treat this issue but my tank has corals i do not want to lose, so copper is out.

have had this setup for about 6-7 months
everything up until the hippo has been fine, and healthy
all the fish in the tank eat alot and i feed them mysis shrimp & Nori

Livestock:
1 tiny black clown
1 bibolor blenny
1 dwarf angel
1 yellow tang
1 sailfin tang
2 damsels
1 blue hippo
1 purple tip Anemone
1 emerald crab
5 different Corals (ones a frogspawn for sure)

Equipment:
Heater
Fluval 206
Sump with live rock and bioballs
Skimmer
UV Sterlizer

Salitnity - 1.021(normally 1.025)
Nitrates - 20-40ppm
Calcium - 520ppm
DKh - 10
phosphate - 0 ppm






i dont want to add copper to my tank.

i am overwhelmed with how many different treatment options there are for this and kinda confused on what to do, and need help before the fish die.


what i have done today about 30 mins ago is add another hear and maxed it out at 85 degrees and maxed out my other to the same 85 degrees, while turned off my lights.