Here is a question to ask Masterderrull... What are u feeding the tangs? It is primarily algae based or is it primarily fish or meaty based food. I would look there. I dont believe that running carbon will do that to a tang. I can say this. I have a purple tang since about quarter sixe up to about 3.5 inch in a 50 breeder with 3 other smaller fish. I never had any issue of HLLE with him and btw he is now in a 120 gallon tang with a hippo & dont have any issues what so ever. I used to have a 180 setup up about 5-6 years ago & bought 2 fish from PSP on Mcknight Rd. I bought a purple tang about 3 inchs & a desjardi both that had an advance HLLE which they said was from running carbon. I bout both for 40 bucks cause i was pretty sure i could recover both fish. I did after about 3-4 months of feeding them algae based pellets soaked in selcon or zoecon. I hope this helps ya.
Jason
Jason
