Landlord,
Quiz time!! Do you have a copy of Fenner's 'Conscientious Marine Aquarist' or Tullock's 'Natural Reef Aquariums' yet?
Your tank is not doomed, but you've just made yourself a ton of work (well, the Tang police might say your tank is doomed, but I won't
)
You realize you still need to add another 75# of LR to your tank, plus critters (unless you already put in the critters, I don't remember anymore), so your biological filtration is not completely established.
You have the following options:
(1) Do a massive water change (30 to 50%) with well equilibrated water
(2) Be ready to perform 10-20% water changes daily (this will drag out your nitrogen cycle, but you've got to consider the cruelty to your fish if you stress them with ammonia & nitrites)
Or, as Splach suggests, temporarily move your Clown & Tang into the 'Surprise Honey' tank until the reef tank is stable. (This will make your 29g overcrowded, but those are the breaks).
I would probably move at least the Tang into the FOwLR tank, even though that will make it overcrowded. The Tang is less hardy, and if the LFS gave you a specimen that carries an Ich infection, at least in the FOwLR tank, you can treat it.
Your priorities are:
(1) Keep fish alive
(2) Keep LR alive
(3) Keep cleanup critters alive
This requires that your chemistry be good (low ammonia/nitrites, heading to zero ammonia/nitrites), and a good bacteria population. Unfortunately, low ammonia/nitrites make it longer for the bacterial population to get established, so you'll have to just do water changes (and we're talking daily if need be) until the nitrogen cycle completes again, and that will take longer because you can't let the ammonia or nitrites get high (as that will stress the h$#^ out of your fish).
Don't be afraid of doing a 50% water change with well equilibrated water (salinity & temperature adjusted; I like aged by at least 24 hrs, but that's probably a feel-good measure).
