2 dead 1 breathing heavy now :(

well i have a protein skimmer, and the return from one of my tanks is not submerged in the sump so that agitates A LOT of water. and makes a lot of noise. i just dumped a bunch of stress coat in the tank, and doing a 5gal wc. maybe this will help. disconnected heat earlier, and new phs now. need to get a better test meter before i do anything else with stray voltage.

 

Are the 2 new power heads stronger than the last? You could have stirred up parts of the tank that didn't get flow and started a mine cycle. Have you tested for amm, trites?

 

yes tested ammonia nitrate nitrite ph

all tested normal.

 

It sounds like here is enough O2, although it makes sense for larger fish to die off from lack of O2 while the inverts would appear normal because they have a low requirment, it sounds like you have a ton of agitation.

Any chance you run biopellets of some sort? They have been known to cause O2 issues in otherwise healthy tanks. Its hard to even say its a toxin because inverts are the msot sensative and usually perish first but you never know. Only reason for angels going first fish wise is they usually have a much more difficult time acclimating than other fish. Have you done anythign other than add PH to the tank recently? Large WC, new salt batch, new dosing or chemicals, increased/ decreased salinity??

 

Onlu thing i run is carbon. Yes mew salt. Went from oceanic to reefcrystals. Did 10g yesterday. 5gal this morning.

 

When did you last change the carbon? To old and it leached back into the system. Switching salt rbands can do it from what I hear that might be the issue or part of it no way of knowing for sure. Did you change salinity, ph, kh, etc?

 

carbon is maybe 2-3weeks old max! and i went from oceanic to reefcrystals, just mixed it to same 1.025 salinity i have always had. i believe it has a higher ph, but i only have done 15gal on a 140gal system, could that really cause fish to die?

 

There is a likely cause of your problem.
1. Oceanic is the worst salt on the market. A couple thousand dollars worth of my dead coral can attest to that!
And 2. If reef crystals gets old or is allowed to hydrate in open air for too long it does some weird chemistry. Happened to me before many years ago

Another option would be bacterial infection. That is why a picture would be helpful.

 

I wouldnt think so, IMO 2-3 weeks is the max life of carbon get it outta there and add some new stuff. Hopefully some others will chime in with great advice Im stumped for ya

 

I mix it let it airate for maybe half hour. Then add it. And the fish look healthy. Nothing new or unusal to show in a pic. Except for weird swimming behavior and heavy breathing.