[Animal-Chin]

How long has your tank been up?

2 years exactly

Any pics of the rock work/tank?

See Attached...

Can you confirm if the cuc did actually die?

Nope but I have a blue star and a tiger tail cucumber that only come out in the middle of the night, one of them may have but I have no idea.

It is a possibility that your rock is leaching out nitrates... If the bacteria died that could cause a spike but one would think that if that happened then other bacteria strains would thrive equaling out the imbalance.

How old is your tank, do you run bp or carbon dose?

I was using NOPOX but stopped and recently set up a biopellet reactor that hasn't kicked in yet. Hopefully it will soon and start reducing.

A pic of the display and sump would help.



Also what is your feeding regimen and how much do you feed?
Skimmer size and info on tank specifications and equipment would help aswell.


Feed frozen food daily, a mix of home made, mysys, krill, the regular frozen stuff all rinsed prior. I have in the sump a sock into a chamber with A SWC skimmer rated for 160 gallons with a phosphate reactor and a biopellet reactor. Sump is totally clean, no ditrutus at all. I do regular 15 gallon water changes every Wednesday.