Tank Crash

[Rivunel]

I have a 20 gallon IM peninsula set up at work since February.
Inhabitants are a dozen sexy shrimp, 2 damsels, 2 emerald crabs, 4 porcelain crabs, a bunch of snail, hermit crabs, a tuxedo urchin and a couple pompom crabs.
This morning when I came into work the water is very cloudy and every shrimp crab and fish is dead. The snaiks urchin and anemones all seem perfectly fine.

I haven't added any new fish or corals in a month.
Yesterday I tested everything alk was 8.4
Calcium 420
Magnesium1440
Nitrates 2<4
I checked my salinity and it was 1.023 I added 2 cups of 1.026 saltwater so the salt content would raise slowly overnight until enough water evaporated everything seemed fine when I left.

What happened? Salinity is 1.025 in the tank now.

 

[devilhunt1231]

Is it possible that someone accidentally dropped something or sprayed something near the tank? Are all the pumps etc still working properly? One possible cause is something died, causing a ammonia spike which killed another causing a bigger spike and so on.
Gary

 

[Rivunel]

Is it possible that someone accidentally dropped something or sprayed something near the tank? Are all the pumps etc still working properly? One possible cause is something died, causing a ammonia spike which killed another causing a bigger spike and so on.
Gary

I assumed the anemones would have been the first things effected if someone sprayed something in my tank. And every anemone looks perfectly fine.

 

[Rivunel]

Is it possible that someone accidentally dropped something or sprayed something near the tank? Are all the pumps etc still working properly? One possible cause is something died, causing a ammonia spike which killed another causing a bigger spike and so on.
Gary

And yes every pump is still working properly

 

[devilhunt1231]

Are you using anything like nopox/carbon dosing?
Gary

 

[Rivunel]

Are you using anything like nopox/carbon dosing?
Gary

...
I did put in a small amount of nopox yesterday it was only 1ml I had never used in this tank but had never had issues before...

 

[Rivunel]

That would be depressing... if that was what killed all of those...

 

[Donovan Joannes]

It could be due to heat... Or electric shock...

If something dies, decomposition usually takes a few hours to start, maybe longer depending on temperature.

 

[devilhunt1231]

With you saying that the water was cloudy and the addition of nopox it's possible that the tank had a bacterial bloom which can strip the water of its oxygen and kill all the type of things that you listed, things like snails etc aren't so oxygen dependent so often survive oxygen depletion, I'd personally consider it fairly high on the possible causes.
Gary

 

[Branespikin]

Heat? What was tank temp? Heat killed my frag tank few weeks ago

 

[Rivunel]

With you saying that the water was cloudy and the addition of nopox it's possible that the tank had a bacterial bloom which can strip the water of its oxygen and kill all the type of things that you listed, things like snails etc aren't so oxygen dependent so often survive oxygen depletion, I'd personally consider it fairly high on the possible causes.
Gary

It seems the most likely cause which sucks on the plus side all the livestock I lost totals just under $100 dollars losing any 3 of the 16ish nems would be worse... just sucks.

 

[amps]

That completely sucks, I'm so sorry. I'd also think it was a bacterial bloom. I had a few blooms when I started vodka dosing on my 10G tank and I was adding only 2-3 drops at a time. I know heavy feeding can also trigger a bloom if that's a possibility.

 

[devilhunt1231]

As I said it's certainly a possibility and I'm truly sorry that you lost the stock, in some ways it's lucky that the anemones survived as if a few of them died you could well have lost everything in the tank but I will say that you aren't the first person to loose stock via a bacterial bloom caused by carbon dosing.
Gary

 

[Rivunel]

I'm happy it happened in this tank... I bought the damsels with the assumption they would die someday if they happened to touch a maxi mini. I really hate that the shrimp and crabs died.

I do feed rather heavily but I never see any nems spit food back up. And I do a 20% water change every week or every other week.
I mean one of the maxi min nems I can feed a piece of shrimp or lrs frenzy as large as a quarter every 3rd day without issue.

 

[Hans-Werner]

When did you add nopox? My suggestion would be to do organic carbon dosing in the morning. So most of the oxygen consumption by bacteria takes place during the day when corals and algae release oxygen.