Ok guys I appreciate all the replies and now that I read through all of them, let me try to comment back to everyone in order hopefully.
So the first issue that was touched on was, too many tangs for a 150. That, I know. I just downgraded from the 210 less than a month ago and everyone has been good up till now. I was trying to get rid of the Vlamingi as it is the largest fish in my tank and I do feel bad that he's stuck in this 150 now. So on that note, I know I have too many tangs but I am working to fix that situation.
The two main issues that seem to have arised from this thread is whether or not to treat the fish and I somewhat agree with both sides.
I have always avoided treatment although I have noticed minor symptoms here and there ever since I upgraded to the 210 four years ago. As mention by some members, all I did in the past was that I would keep the fish well-fed, soaked food in garlic and kept good water paramaters. Everything seemed to work fine up till now, the downgrade went smoothly but the change of environment I am more than sure, stressed the fish beyond belief.
The main difference between the current location between the 150 now and the previous location of my 210 is big. The 210 was in a basement, very rarely trafficated by anyone in the house except me and probably a darker environment overall given the smaller windows. The 150 on the other hand, is now in a living room in a corrner, about 20 feet from the front door and a few inches from windows on both sides. The fish that were used to a darker/slower outside enviroment are now in a brigther/busier environment which I'm sure has added a lot of stress to all of them. Normally I would just let the ich sort of 'blow over' but I don't think that this time I can take that chance. It has always disappeared with minimum amount of time but right now it seems to be too infested to change that, especially on that poor hippo tang. I will monitor the tank some more this week and try to feed more frequently and do more water changes. I won't give it more than a week though because I don't want to start losing fish.
Honestly at this point it seems like a lose lose situation, if I do treat the fish I might cause deaths by the stress they'll go through being caught and if I don't do anything they might just die by the overinfestation of ich. I do have a cleaner wrasse that's working hard at keeping things in some sort of check but there's only so much one fish can do to help out 23 other fish.
At least it seems like I did get the answer to the original question of this thread, so if worst comes to worst, I will begin treatment next week in a large Rubbermaid or garbage can.