Ok given this info:
It's been running and stocked a month, so does that mean it's only gotten 2 50% water changes so far?
The fish were likely suffering from ammonia and/or nitrite poisoning in that case. The nitrates are the least of the problems, IMO. It is MUCH LESS toxic of the three by products, and unless you have particularly sensitive stock (some invertebrates such as snails and shrimp, and even fewer actual fish), the nitrates are unlikely to have caused the deaths.
When you are doing a fish-in cycle you will likely need to be doing daily water changes to keep ammonia in check; and nitrite next when the ammonia starts to process to nitrite. This process can take alot of time; fish-in cycles take notoriously longer to stabilize vs fishless cycles...because of the water changes necessary in a fish-in to keep your stock healthy. The process might be shortened had you gotten either a working bacterial supplement (Tetra's Safe Start is the only one I know of that works well), OR seeded your tank using existing filter media from a cycled tank.
Of the bacterial colonies you do have; many might have died during the power outage. Rather than reiterate, I suggest reading this: http://www.thinkfish.co.uk/article/D...th_Power_Cuts/
it explains better in detail what happens during a power outage, with lengths of outages included.
Thing is...it sounds like your tank wasn't cycled. But even in a cycled tank a power outage that long can be disastrous unless very specific measures are taken as outlined in the link I gave you. I'm not sure based on what you've said so far that you are familiar with the details of the nitrogen cycle. If you have any further questions, please feel free to ask. :)
Oh..and smack your LPS in the forehead about the bamboo shrimp. A bamboo shrimp should never be recommended for even a newly cycled tank. While it is DOABLE, it is not ideal for them; as they are filter feeders and their source of nutrients is in the water column in the form of micro organisms. A newly cycled tank will not have enough for them to eat; unless you are target feeding them with a turkey baster. They only scrape their delicate fans on the surfaces if they are starving.
Again, I'm sorry for your troubles. It is unfortunate but most stores do not provide information about the nitrogen cycle, and it is a necessary thing to know about, in my opinion.
*I'm curious about the "clarifier." What product is it exactly? Water clarifiers are almost never necessary, as all they do is clump up fine matter so it can be caught by your filter.