Overnight casualties Kole tang mated B/W Ocellaris'

So my 75g in my gameroom took a major hit last night. When I went to bed, everything was healthy and looking great. This morning death everywhere. Went to feed my tank and no Kole Tang. Neither of my mated B/W Ocellaris' Only my Chromis and my six line were present for chow. Close inspection revealed my Tang and both clowns dead up under the rocks. What happened? I don't know. I keep looking and notice my three inch fuzzy shroom has detached. Looked for a while longer and found my shroom chewed up in a 1200 gph wavemaker. Removed corpses of all fish and the shroom. All my corals are unharmed. Chromis and six line eating and frisky. Checked water params.All good.

PH 8.4
Nitite 0
Ammonia 0
Nitrate 15ppm
Calcium 470
temp 78

Corals

Star Polyps
orange dendro
3 X Torch
2 X Duncans
3 X Zoas
green montipora

Tank still pretty young only about three months old, but water chemistry has been monitored every other day, and livestock added slowly. Probably a little too fast, but i don't think that's what caused the crash. Anyone have similar experience? Any advice welcome. please don't try to spare my feelings on this one, I really need to know what I did wrong.

 

it honestly could have been from adding things in that amount of time, IMO for 3 months thats a little to much

 

I should add that this tank is made up of a 55g that I broke down, so 80% of the rock and 30% of the water came from that tank which was well established. I know that this doesn't keep a tank from cycling, or even really speed up the maturation process that much, but I do have a healthy pod population and coralline starting to get established. Not making excuses, just putting that out there.

 

how recent did you switch tanks?

 

Three months ago

 

dont know what to tell ya, only thing i could think of is if the power went off in the night. Sorry i wasnt to much use BUMP

 

Sorry about the loss, did the dead fish show any signs of disease when you found them? like covered in slime or marks on them?

 

Really sorry to hear about this!! Just awful.

 

Just an idea...could it possibly be low oxygen level? Is your tank covered,have surface agitation and good flow?

 

Thanks for the support. Found one chromis dead this morning. I don't know what is going on, but other than the clowns, which did have strange white marks all over them, none of the other fish looked ill before or after they died. The white stuff on the clowns wasn't ich though. It was more like IDK some sort of strange spider webish type discoloration. It covered their bodies from nose to tail. Could have been some type of goo, but I really don't know. As for the oxegen question, I do have a canopy over the tank, but it is open in the back. I'm running two 1200 gph wavemakers, one of which is near the bottom and aimed moreor less up, so the surface of the water has good movement. My fuge is in a cabinet under the tank, but the back to that is open as well. My protein skimmer is rated for a 150 and runs all the time, so that should help as well.

Side note, I have also had a strange algae bloom this A.M. the tanks walls are about 20% covered, which never happens, my CUC can easily handle the algae under normal conditions. I've thought back carefully about any changes I made recently, and the only thing that I can think of is I just put in a new t-5 fixture to replacemy old PCs. I did that on Wednsday, which does make the timing suspect. I did test for stray voltage though, and the circuits are clean.

Does anyone know whether or not my shroom could have released toxins when the powerhead choppedit up?

Any thoughts ? I'm hoping to save what's left!