I agree with you that the site is full of jerks but you can also talk to the experts like Anthony Calfo a auther on fraging vary well known i bet a few members on thise fourm have read,own or heard of some of his books.
I have found that in life the majority of people are jerks wich is y i love this fourm every one is so nice.But one RC they have 140,544 members i am amazed at the ammount of friendly people on that fourm i would say around 100,000 are nice and the other 40,544 are blood sucking monsters.
Lynden it also depends on what type of tangs
Acanthurus achilles, Achilles Surgeonfish, 100 gal (380l).
Acanthurus coeruleus, Atlantic Blue Tang, 75 gal (285l).
Acanthurus japonicus, Powder Brown Tang, 75 gal (285l).
Acanthurus leucosternon, Powder Blue Tang, 100 gal (380l).
Acanthurus lineatus, Lined or Clown Surgeonfish, 180 gal (680l).
Acanthurus nigricans, Whitecheek Surgeonfish, 75 gal (285l).
Acanthurus olivaceus, Orangeshoulder Surgeonfish, 135 gal (510l).
Acanthurus pyroferus, Mimic Surgeonfish, 75 gal (285l).
Acanthurus sohal, Sohal Surgeonfish, 180 gal (680l).
Acanthurus tristegus, Convict Surgeonfish, 75 gal (285l).
Acanthurus tristis, Indian Mimic Surgeonfish, 75 gal (285l).
Ctenochaetus hawaiiensis, Chevron Tang, 100 gal (380l).
Ctenochaetus strigosus, Kole's Tang, 75 gal (285l).
Naso brevirostris, Spotted Unicornfish, 180 gal (685l).
Naso lituratus, Orangespine Unicornfish or Naso Tang, 135 gal (510l).
Naso unicornis, Bluespine Unicornfish, 200 gal (760l).
Paracanthurus hepatus, Pacific Blue Tang, 100 gal (380l).
Zebrasoma desjardinii, Indian Ocean or Red Sea Sailfin Tang, 135 gal (510l).
Zebrasoma flavescens, Yellow Tang, 75 gal (285l).
Zebrasoma scopas, Brown Tang, 75 gal (285l).
Zebrasoma veliferum, Sailfin Tang, 135 gal (510l).
Zebrasoma xanthurum, Purple Tang, 100 gal (380l).
You will note that none of these minimum sizes are less than 75 gallons. If you have a tang in a smaller tank, you should expect that some people will give you a hard time about it. Expressing outrage about that could result in suspension of your posting privileges. We are not, BTW, giving a free pass to the self-styled "Tang Police" to be abusive.
3. The above sizes assume a standard rectangular shape with plenty of open swimming space. If your tank is full to the brim with coral, your tang won't be happy. Tanks 125G or larger are assumed to be at least six feet long (approx. two meters). Where possible, choose longer rather than deeper shapes. While smaller species may be OK in a four foot tank, they will probably do better in a five foot or longer tank.
4. We do not condone the practice of keeping more than one specimen of the same or very similar species together in the same aquarium, except possibly for Zebrasoma species in a very large tank.
5. If you wish to keep multiple dissimilar tangs in the same aquarium, we recommend you have an aquarium significantly larger than the sizes listed above.
RC has that on the top of there reef fish page.