what on earth could go wrong

[klavmaister]

Can someone tell me what are the classic reasons why an aquarium crashes. right now the new aquarium seems to be in great shape. Good water values, great equipment, stable salt values, temp etc.

250l 3 months old, 2 clown, one seaweed (tiny) 4 snails 5 soft corals one lps. filterroll skimmer offline (nothing to do)

Ammoni = 0
Nitrite 0
nitrate ~10-15
Alk = 8.4
calcium 390-420
temperature 24c
salt 1,025

but here I sit and think, what can crash my mind.

 

[vtecintegra]

Heater failure. You should always have a secondary way of turning the heater off if it ever sticks on. Some people put their heater on a heater controller, or plug it into an Apex, GHL, or Hydros.

 

[bushdoc]

I think you should stop worrying.
If you don't leave on prolonged vacation and inspect your tank daily, odds of crash are low. Surely heater may fail, but I have 30 gal tank, which is my repository for redundant livestock, which has been running for 5 years without much maintanance and without failure.
If you have ATO, then it might be another point of failure, my ATO just forgets to add water sometimes, so I check it regularly and put it on timer, so it resets itself few times a day. Of course I never forget to refill ATO reservoir
Relax, have fun and keep reading this forum, so you'll figure out what issues reefers tend to have.