Thoughts on unnexplained (and very sad) die-off

[jostafew]

So it would seem that whatever was affecting the livestock is still present. Last night I picked up two cleaner shrimp that were to provide some life in the tank for the next 2-3 months. This morning I found them both dead, pretty much un-moved since they were introduced to the tank last night.

Now either something went very wrong during acclimation, or there's some kind of mystery death in my system which I can't pinpoint. I've acclimated many an invert before, always succesfull. I'll go over things from this time though, maybe something will stand out:

Shrimp spent about 1/2 hour in the bag on the way home from the LFS, mix of sitting on the seat and in my lap to maintain temp.

Got them home and into a bucket with a thermometer, started a slow drip from the DT. When they went into the bucket, their water temp was 74 something. Using my standard method of warming the bit of water (glass full of warm water placed into the existing water), I slowly brought the temp back up to about 78 deg.

Two hours later, temp sitting steady at 78, time to go into the tank (which was at about 80deg.). Scooped up one shrimp and gently into the tank, where it clung onto my fingers for quite a while. Finally convinced it to let go when it sank (not swam) down to the bottom. Same thing for the 2nd one. They looked stunned, the odd cleaning of antennae, but no big movements.

There they stayed overnight, this morning, and now at lunchtime I happend to be home and checked them again, at which point they were both dead.

Now I'm really getting puzzled with this whole thing, it's like there's some mystery poison in the tank that's killed ALL of my fish and inverts, and putting a hurt on my corals. My LPS open up to feed at night, but have absolutely no extension during the day. All are completely deflated.

Ran a few measurements again last night, SG was down a little (1.024) so I slowly added the necessary salt to bring it back up. Alk was still down (6.7)despite my last dose a few weeks back, so I added 1/3 of the necessary dose to bring that back up as well. Other than that, no ammonia, no excessive nutrients (very little algae groth), skimmer's long settled down after the move. Running carbon in a TLF 150 reactor, and a poly filter. Baffled....

[jostafew]

SOLVED!!!

Had a good chat with the LFS eliminating a bunch of possibilites and finally we settled on the theory that I had a bad batch of salt. Timeline fits, slow decline starting in the summer time getting the worst around the end of the year. Started using that bucket (which had a noticeably different texture) in the spring of 2012 and just finished it when the new tank went up in Jan which coincided with the loss of my last few animals.

As a verification I set up the QT tank at work with new water and moved all existing live rock (and corals that had encrusted) into that tank for holding. I then completely drained the main tank, and got rid of the existing sand. Iin went brand new water, new sand (live) and a couple pieces of new rock. A couple quick adjustments to Calc and Alk and my levels were spot on target.

After allowing it to cook for a little while the corals in there were looking noticeably better. Confident that the tank was more habitable I tried a couple cleaner shrimp which have been doing great for a few weeks now. That told me that my hardware was good, no toxins leaching from the tank setup.

Next step was new sand and new water in the nano but kept the LR that was pulled from the big tank back in November. After some time to stabilize, in went some test critters, which again are doing great. So as of late 2012 the live rock was not toxic.

Last confirmation was to place a canary (peppermint shrimp) in the QT along with the live rock and see what happens. This would be the highest concentration of rock to water, so if there was something toxic leaching from the rock it would show here for sure.

I'm happy to say that the shrimp is still looking good, so the rock is safe and come home finally!

So problem confirmed, I had a bad batch of salt that spiked my Calc and Mag and who knows what else. Lesson learned; measure the first couple buckets coming from a new batch of salt before going into the tank. Pretty scarry though, I never would have thought something like this could happen. And of course when things start going badly what's the first thing to do.... water changes.... In my case just making the problem worse.

I'm not going to name the salt brand as I'd used it for a couple years before hand and I know tons of people who use it without problem, but to the knowledge of the LFS I am the 2nd person this has happened to so it does happen.

Hope this helps someone to find the cause of their problem before they lose all their beloved livestock like I did.

Happy reefing!