Something has gone wrong and I can't figure out what

Last night I did my usual tri-weekly water testing after noticing some things just "acting funny" and found something a little off: ammonia 0; nitrites .25. nitrates 30ppm. They are all usually 0 across the board. I attributed it to extra food that day, which I had been using to try to lure my damsel's into a trap. I left it for the night for the tank/skimmer to break down. I fear this was a terrible, terrible mistake.
Today I got home to find my tang near death. tested again: ammonia 0, nitrites 0, nitrates 140ppm
I did a 30% change, added new carbon, cleaned out filter and skimmer. Added an airstone. Am currently waiting a bit to re-test.
I am trying to figure out what has happened. I really havent changed anything. The only thing I did prior to this was to remove some frag's and an urchin. The only thing that sticks out is adding a phos-zorb pad, but have heard other users using it here with safety, so I don't know if that could have done it. I removed it to be sure. I dont see how the little bit of extra krill that day could have mucked things up this bad, but I am not sure
If anyone has any insight, see's anything drastic that I did wrong, or thinks I should do anything additionally, please, feel free to share. I am not sure if my prized naso will make it through the night.

 

No that stinks sounds like your in the same boat im in.

 

oh man, 130 ppm thats a pretty drastic increase, hmmmmmm, hmmmmm, only thing i can think of beside a huge rotting fish in there , is that maybe some kind of cleaning product or something along those lines found its way in.


also how old is the tank?

 

The tank is 6 months old. I did a head count and the only thing I can't currently find is a single hermit. Even if it is in fact dead, I highly doubt it would cause this.
Everyone else in the tank looks ok. My torch doesn't look as happy as it could be, but thats to be expected with how touchy they can be. My tang is barely able to stay upright.

 

yeah no way a dead hermit will do that, and i dont think the krill would be enough to do that as well. id do some water changes and see if you can get it to go down,. if your sig. is still accurate maybe your fish are getting larger and your pushing the limits of the 40 gal, but if your nitrate were at zero id think it would be a slower rise over longer time as your fish grew.

what method of nitrate reduction are you using.?
(macro algae, absorption media, lots "O" LR, coiled-denitrater, ect......)

whats the max size of them naso's?

 

All the fish are fairly small. Naso is maybe 3-1/2"? I know they eventually get big, but I have a 120 in the works so that wasnt going to be an issue.
As far as filtration goes, I have lotsa LR. I honestly lost count of the actual amount, but I would say 70-80lbs., maybe even more 50lbs LS. I have an aquaclear 70 filter with the sponge and carbon (changed every 5 weeks or so), and an octopus BH-100F skimmer rated at 110 gallons. So yeah, I have quiet a bit of filtration.

 

Dude, you have death in there somewhere. You don't run a cansister filter or filter socks, so that is out. The AC70 you clean. The krill isn't enough to do that much as stated above. Now, you are a base rock kind of guy, right? If you put live rock in and there was a larger nocturnal hitchhiker that died, that could be the culprit. Otherwise, it is a mystery. No anenome. What else would produce that kind of waste that quickly?

Do a series of back to back 30% water changes to get that nitrate level under control. Dose with Prime daily. I also want you to look into a fuge of some sort. A HOB if there is room.....A denitrator from Tangster if there is not. Something to thwart this in the future. Wow.......weird. I will think on it some more. I am stumped.

Also, for the time being, if you don't already, cut the feeding back to twice weekly. That will cut out the exogenous introduction of waste.

The only other thing I can think of is take out each rock and smell it. If it smells rotten, something is dead inside. At the same time you do that, get those damsels out of there. Then do a WC and call it good.

 

Have done follow up testing:
0 ammonia, 0 nitrites, 15ppm nitrates. I will wait till tomorrow when I get home from work again until doing anything else. Above params are acceptable, compared to earlier. I dont want to change more water than I have to.
I did use some live rock, although that was added a long time ago. I watch my tank late at night quiet a bit, I am pretty sure there is no hitch-hiker large enough to do this.
What I am maybe thinking is sponges? I have had 3 threads in here lately asking about what something was, all turned out to be sponges. They seemed to have been booming in my tank for whatever reason. If I remember right, they release toxins much like an anemone if they die. Maybe a a lot more unseen sponges died, and I would have never noticed? IDK, I am just trying to brainstorm what happened.

 

Good to see that the nitrates are back down to near-zero levels again.



One recomendation:

You should change/clean that sponge at least once every two weeks, and the carbon every three to four. Five weeks is too long, in my opinion.

 

Duly noted reeron. Consider it done from here out. I am also wondering about cleaning out the skimmer. I never have.