No discernable cycle - ready for fish?

[waterbourn]

I have had my 55 gallon set up with 55 lb LR and 75 carib sea sand for about 1 week. Both the sand and rock came from an established tank, complete with critters and coraline algae. I also got about 20 snails and 15 hermits in the tank also. I have been testing the water everyday and I think the ammonia might have gotten to 0.25 mg/L one or two days. The color was still close to zero both times so I really don't know if the ammonia was ever really detectable. The nitites have been zero the entire time. From asking questions here and researching, I think I either had a very small cycle or no cycle at all. Do you think I am ready for a fish or two? Wouldn't the hermits and snails produce some waste to jump start a cycle if one was going to happen. I am definately not going to throw a shrimp in the tank as I am not a big fan of this approach.
On a side note - my calcium has already dropped from 400 to 350 in one week. Will I be ok adding calcium one day and the carbonates the next to get my calcium back up and stabalize my alkalinity? I have some Seachem Reef Advantage calcium (for calcium) and some Reef Builder (for carbonates).
Also any idea of when I should go ahead and do a water change?
Thanks!

 

[trikonreef]

Did you add any food or an amonia jump start? I'd add a cheap and hardy fish just to be safe. Might not be enough waste built up in the tank yet to get a good cycle.

 

[ophiura]

Before adding any fish I would just feed the tank as you would with a fish in it for a good week. You can try pushing the tank harder as well with some shrimp.
If the tank is cycled, it will make no difference.
If the tank is not cycled, you'll be happy that you learned it now than with a fish.

 

[phixer]

At this point Id change 5% and introduce one damsel.

 

[ktsdad]

Since your rock and sand both came from an established tank, and I assume it was a short drive from the old tank to the new, your tank may already be cycled.
We had the same situation. I took 100 pounds of live rock out of our 2 established tanks and put them into our new 250 with another 120lbs of dead rock and 220 pounds of dead sand.
We waited 4 weeks and also never got a reading of over .25 on the ammonia test kits (I used 3 different kits to make sure).
I did feed daily (as if there were fish in it) and put a chunk of raw shrimp. Still never got any kind of spike.
After 5 weeks we introduced our 6 fish, one a week. All has been good.
Moral of the story......
You may be cycled and ready, but you not.
Start feeding a pinch or so (more than your crabs can eat, you want excess waste) of food daily. After a few days, check your levels. If ammonia and nitrIte are still not detectable then I would say you are safe.
Good Luck