Sudden death?

[Antmonger]

I have a 240gal reef tank with softy’s and LPS
Alk 10-10.5 range
Ca 420-450 range
Mag 1250-1300 range
Salinity 32
Nitrates 15-20 range
Temp ranges 78.1
Radion xr30 light it has been on the same schedule for years

I started to do maintenance, as-well as needing algae removal from the glass and I noticed something strange? All the fish started to freak out almost like they were dying and started to breathe heavily!!! But the only thing I had noticed was that my ORP dropped .!!

So I immediately added prime and tossed in an air stone. It seemed to help. Has this happened to anyone before or have you seen this happen before .??

(30 mins) - valentine puffer and the maroon clown have passed but all the other fish seem to be alright.

 

[Jay Hemdal]

I wonder if I potentially have toxic algae….
And the OPR dropped from the Prime “dechlorinator”

In your original timeline, it looked like you added Prime after you saw an ORP drop. I still think some chemical reduction happened that took up the available oxygen.

The fish were affected, but how about any invertebrates?

Jay

 

[Antmonger]

In your original timeline, it looked like you added Prime after you saw an ORP drop. I still think some chemical reduction happened that took up the available oxygen.

The fish were affected, but how about any invertebrates?

Jay

Invertebrates are still alive

 

[vetteguy53081]

Invertebrates are still alive

Inverts have no gills and will often survive such instances

 

[wculver]

whites-

I've actually heard of this happening in dense sand beds during cleaning. Gasses build up in the sand bed, including under the rocks, then when disturbed they are ejected into the water column with negative effects on the fish. H2S is commonly referred to as one of those gasses that forms under anoxic conditions.

 

[Gatorpa]

In your original timeline, it looked like you added Prime after you saw an ORP drop. I still think some chemical reduction happened that took up the available oxygen.

The fish were affected, but how about any invertebrates?

Jay

He’s got a pretty decent sand bed.
If he was getting low into the sand bed with the Mag Float he could have released some H2SO4, although he might have noticed a sudden smell.

Ive seen it before. (smelt it really)