Im gonna jump in here and throw my experiences in.
I have a 29 gallon tank, and would probably be told its overstocked too. (click the myinfo button to see what I have)
However, all my bad chemicals are 0ppm except nitrate which floats between 10 and 20ppm and phosphate is like .01-.02.
I have 40 or 45 lb of live rock, and I have a 10 gallon sump with a little plastic bucket i poked holes (lots of holes) in that just floats and has calerpa algea in (and pods
as I noticed of today, woot!)
When my tank cycled it took about 2 weeks
I am a research whore when it comes to this stuff, and one thing ive learned, your going to get about 50million different opinions/timeframes/suggestions/etc. Heres what I would do if I were you.
1st thing you want to do is pick up a protein skimmer. With these you get what you pay for, stay away from Prizm. Coralife super skimmer 65 is good if your on a budget, Aqua-C Remora if your not.
Ditch the bubbler, with a filter and a skimmer, the water will have O2
Get yourself an Aquaclear 50 or something, some carbon filtering never hurts.
Assuming you didnt typo (and this is why i left this for last) your gonna need to get more live rock. 45lb is a good aiming point, personally i feel like 60 lb is like lookin at a tank full of rocks and oh, theres a damsel in there... somewhere...
IF.... if.... you need more live rock than you have, you will probably kill what you have in there. Die off from the rock, even if its cured (and espically if its not cured) will start the cycle which we assume your tank never did... Kurt explained this above. If you can get cured rock, your fish might survive, but see if you can maybe give your livestock to the local fish store to hold for you while the tank cycles.
If you can, in the future, consider a sump. You can store more live rock down in it, and free up room in the main tank. You can also set up a ghetto-fuge like I did and help control nitrates.
As far as the crab goes, they are right. He will get huge... in a few years. Maybe a year depending on how big he is right now. So its up to you if you want to deal with it now, or later. If you want to enjoy him while hes small, I say go for it, just keep in mind he will eventually get too big, that is certian. Dont worry about it though, I made so many dumb livestock choices when I was starting out.... oh man lol.
you say you want low maint. tank. It is possible to have a low main 29gal tank, with a refugium. Right now my tank, i top off evaporated water, feed my fish daily, and test water weekly. I havent done a water change in quite a while and my water is fine. Some people would argue you should still do water chages even if water levels read 0 or very low, but Ive read so many articles on it I feel my tank is fine and the literature Ive read reaffirms that notion. Happy active fish, no signs of stress, no illnesses, pods
in the fuge. (this is for FOWLR
, if you do coral one day, water changes would be a more pressing matter)
and in my opinion... ditch the damsel. they are such a pain in the bass (yukyuk a fish joke!) they are mean, they claim like 3 or 4 cubic feet of territory, which is like... 1/2 of a 29gal. There are just better choices imo
so to recap:
30-45lb live rock
try to give the live stock to a lfs
to hold while the tank cycles. if you cant get cured live rock, you fish will die.
real quick last thought: food. frozen mysis shrip, frozen krill, or Spectrum Thera by New Life (pellet food) is a good menu for fish, they flip out for the pellet stuff.
this is my $0.02, based on my trials and tribulations. I was where you are a few months ago, probably even worse off. I rescued a tank from my room mate, and had 100% no idea what I was doing, nor did he. I had a clown that survived a cycle, which was very bad. Folks on this forum want to make sure your animals are treated as humanely as possible, which is why the suggestion to start over has come up. I have attempted to give you a second option, but I dont claim it to be better than any other route.
ps, if you looked at myinfo, yea i do have a imperator angel in a 29. no you cant have one
i have a 150 gal
tank in waiting that will be its new home in about 2 months.