Wich tang 4 algae eating?

Clean up crew isn't much different than a tang. Both are employed to eat algae.. Tangs on the otherhand(zebrasoma) will eat HA unlike most inverts employed to do so...

 

Yes tangs will eat gha sure but reducing your nitrates and phosphates and keeping doog husbandry will do that too! Point it tangs arent the answer to gha water quality is. Its a tought battle with gha I have been there but never looked to tangs to resolve it. I am just trying to give advise on the cure for it not the band aid. You want to know what tang to eat algae? they all do.

 

Yes, true statement but if one wants a tang to simply have then its would make sense to get one that eats any algae in the tank if one has it.

I believe in water quality as the remedy for just about every single problem in the tank, from algae to parasites to poor growth in fish and corals to gelbstoff.

I have always promoted water changes as the key to success, heck when I have something wrong at the shop just about the first thing I do is a W/C... So I hear you on the water quality issue.

Plus they all might eat algae but they all eat DIFFERENT algae.. ;D

 

This is why I have 5 tangs in my tank! very well put btw.

 

Just to bring this all back around, the OP was looking for a tang for a 72g tank.

Lots of people keep Zebrasoma tangs in tanks that size but I think (IMO of course) you need to either plan on moving the fish out to a larger tank as it outgrows the tank (which could take a few years depending on the species I think but almost certainly it's going to keep growing) or you may have to deal with a fish that is oversized for the tank which could mean excessive aggression/territoriality, skittishness, difficulty feeding, or sickness/death eventually.

The smaller Ctenochaetus, bristletooth, tangs are a few inches smaller than the smaller Zebrasomas, so you could theoretically keep them more easily in a smaller tank for their entire lifespan.

It's all up to the keeper. I personally fall on the optimistic side and do not expect for my fish to live short lives in my care. Some people don't mind trading out fish that get too big or don't mind that their fish die every couple of years even though their natural lifespan is 5-10 times as long as they live in their aquarium. Hopefully this isn't too preachy!