Incorrectly Cycling a tank adding "cured" live rock

I seem to have something going on in my tank. I ordered snails and hermit crabs from two different sources and the snails failed to move around the tank after the first couple of days. The first batch lived about two weeks and died one at a time over that time span. The second batch is alive now but they don't seem to move around and never get on the glass and lie upside down most of the time. I cant find anything wrong with the water.(ph 8.4,ammonia 0,nitrite 0,nitrate 0-.25,phosphate 0.1,silicate <.02,iodine .05,calcium 425,magnesum 2000ppm,carbonate 3meg/l,borate 1meg/l,total alkalinity 4meg/l) Also I have lost two colt corals after about 2 weeks at seperate times.the tank has been setup since december. Do you have any idea what's going on?

Who are these 2 different sources? (your suppliers?) did you buy online, or in a store?

When you say you bought a "batch" of snails... exactly how many is that?

Your saying your magnesium is 2000 ppm... what test kit are you using to get that reading?

Briefly tell me how you went about adding your liverock / cycling. did you add liverock *after* the livestock?

Your tank is still fairly new however colt corals are very hardy. I've found snails to be somewhat unpredictable in regards to their resilient, or if you will hardiness.

Answer the above questions may help identifying your problem although offhand I suspect you may have received poor quality livestock.

The two sources I ordered snails from was GARF and Worldwide Pet Supply on the internet. We got 30 to begin with from GARF. They consisted of half turbo and half astrea. The second batch of 12 was fro Worldwide Pet Supply. Do you have a suggestion for a better source?

Garf has been around for a while and I'm sure as good of a source as any. I don't think thats the problem

The test kit I'm using is from SeaChem. I could be off on the magnesium level because I didn't do a reference test at the same time. The 40 pounds of live rock was bought from a local store and was put in first. It was never put in his tanks because he had to order it and have it imported from Fiji. It was supposed to have been cured and looks like it has.

Ok. live rock doesn't "look" cycled. And you don't cycle it with damsels.From your saying the liverock wasn't in the dealers tanks leads me to believe it was *not* cycled.

Liverock has millions of life forms on it
There is life on and *in* the rock that you cannot see, some actually fairly large creatures
When the rock is shipped some of the life on and in the rock will die - despite it previously being cured
when you buy new liverock, it is not recommended that you add it into a tank with other living things

My recommendation on starting a reef tank

Buy all or most of the liverock first
Cycle the liverock ammonia nitrite nitrate so you get a zero ammonia and nitrite (1st cycle)
next add all or most of the invertebrates Cycle ammonia nitrite > nitrate (2st cycle much smaller)
next add all or most of the corals Cycle ammonia nitrite nitrate (3rd cycle less than the second)
next add all or most of the fish Cycle ammonia nitrite nitrate (4 th cycle ) I
the key to add and have the liverock cycle first, inverts second, corals, third and fish last

I cycled it with damsels. I have a 40 gallon tank with a 20 gallon sump that contains a live sand plenum system, protein skimmer, and a Magdrive 950 return pump. For lighting I have a duel power compact which is 96 watts each. 1 blue and 1 white bulb. In my tank right now I have 4 damsels, 1 yellow tang, 1 rock goby, 1 tongue coral, 1 yellow polyp, 1 cauliflower polyp, and 1 clove polyp. When the colt coral started looking bad I transferred it to a sick tank, but now I have noticed that my polyps aren't opening as they were before. Could the colt coral have contaminated my tank? Also, should I wait to add corals until the tank is aged longer?

Definitely. You have to cycle all live rock despite claims that its fully "cured" Live rock, when taken out of water and transported will always have significant die-off on it. so you need to cycle it fully in a separate tank, until you're confident the nitrite to ammonia cycle have fully taken place.